NL2015575B1

NL2015575B1 - White rust resistant chrysanthemum plants.

Info

Publication number: NL2015575B1
Application number: NL2015575A
Authority: NL
Inventors: Cornelis Maris Paulus; Wain Peter
Original assignee: Fides Bv
Priority date: 2015-10-06
Filing date: 2015-10-06
Publication date: 2017-05-02
Also published as: CO2018004683A2

Abstract

The present invention relates to white rust resistant plants of the genus Chrysanthemum and to seeds, plant parts, plant cells and progeny thereof. The present invention further relates to means, and particularly molecular markers for identifying white rust resistant plants of the genus Chrysanthemum. Specifically, the present invention relates to plants belonging to the genus Chrysanthemum, wherein the plants are resistant to white rust and the plants comprise in their genome at least one white rust resistance gene, the at least one white rust resistance gene is genetically linked to a genomic nucleic acid sequence comprised in the genome of the present plants and is represented by SEQ ID No. 1 or SEQ ID No. 2.

Description

WHITE RUST RESISTANT CHRYSANTHEMUM PLANTS

Description

The present invention relates to white rust resistant plants of the genus Chrysanthemum and to seeds, plant parts, plant cells and progeny thereof. The present invention further relates to means, and particularly molecular markers, for identifying white rust resistant plants of the genus Chrysanthemum.

Chrysanthemums, also designated as chrysant(h)s, are flowering plants of the genus Chrysanthemum in the family Asteraceae. The plants are native to Asia and north-eastern Europe and are comprised of a large number of horticultural varieties and cultivars.

Several genera of Chrysanthemums amongst which the economically important florist's Chrysanthemums were classified in the genus Dendranthema in the past. However, presently, the florist’s Chrysanthemums are reclassified as Chrysanthemum indicum, restoring the position of these Chrysanthemums in the genus Chrysanthemum.

Naturally occurring Chrysanthemum species are herbaceous perennial plants.

These Chrysanthemum species display alternately arranged leaves divided into leaflets with toothed or occasionally smooth edges. Chrysanthemums were first cultivated in China as a flowering herb as far back as the 15th century BC and over 500 cultivars had been recorded by the year 1630.

Presently cultivated Chrysanthemums display a more pronounced and aesthetic flowering as compared to their wild relatives. The flower heads occur in various forms, and can be daisy-like or decorative, like pompons or buttons. This genus contains many hybrids and thousands of cultivars developed for horticultural purposes. In addition to the traditional yellow, other colours are available, such as white, purple, and red. The most important hybrid is Chrysanthemum x morifolium, also designated as Chrysanthemum x grandiflorum, being primarily derived from Chrysanthemum indicum.

Chrysanthemums can be divided into two basic groups, garden hardy and exhibition. Garden Chrysanthemums are perennials capable of wintering in most northern latitudes. Exhibition varieties are generally not capable of surviving winter. Garden Chrysanthemums can be defined by their ability to produce an abundance of small blooms with little if any mechanical assistance, such as staking, and being able to withstand wind and rain. Exhibition varieties generally require staking, overwintering in a relatively dry, cool environment, and sometimes the addition of night lights.

White rust is a disease in plants caused by oomycetes or water moulds such as Albugo Candida or one of its close relatives. Oomycetes or Oomycota form a distinct phylogenetic lineage of fungus-like eukaryotic microorganisms. They are filamentous, microscopic, absorptive organisms that reproduce both sexually and asexually. Oomycetes occupy both saprophytic and pathogenic lifestyles, and include some of the most notorious pathogens of plants, causing devastating diseases such as late blight of potato and sudden oak death. The oomycetes are often referred to as water moulds, although the water-preferring nature which led to that name is not true of most species, which are terrestrial pathogens.

Signs and symptoms of a white rust infection include chlorosis on leaf surfaces, white blister-like growths on the leaves and on the stems of the plant, and swelling of the roots. In addition, abnormalities in the growth of the host can occur with more serious infections. These abnormalities can include deformation of flowers, twisting or distortion of the plant matter, and sterility.

In Chrysanthemum, white rust is a disease generally caused by the pathogenic oomycete or fungus Puccinia horiana. Chrysanthemum specific symptoms include white rust spots on the upper surfaces of leaves. These spots are initially pale-green to yellow in colour and up to 5 mm in diameter, but may turn brown as the tissue becomes necrotic. On the underside of the leaf, the spots develop into pink or white pustules that become prominent as the teliospores develop.

The disease is generally carried on infected cuttings and plants, including cut flowers, of glasshouse Chrysanthemums.

Until 1963, Puccinia horiana was confined to China and Japan. However, it has since spread rapidly on infected imported cuttings and is now a feared and serious disease in nurseries in Europe.

Preventive spraying with fungicides is effective but costly. Active ingredients found useful include oxycarboxin, triforine, benodanil, triadimefon, diclobutrazol, dibitertanol and propiconazole. Verticillium lecanii has been suggested for biological control of on glasshouse Chrysanthemums.

Considering the considerable damage to Chrysanthemum cultivation by white rust, there is a need in the art to provide new genetic resistant sources, i.e. there is a need in the art for new resistance genes providing durable white rust resistance to plants of the genus Chrysanthemum.

It is an object of the present invention, amongst other objects, to meet the above need of the art.

According to the present invention, this object is met by the present invention by providing plants, plant parts, seeds and means as outlined in the appended claims.

Specifically, according to a first aspect, this object of the present invention, amongst other objects, is met by providing plants belonging to the genus Chrysanthemum, wherein the plants are resistant to white rust and wherein the plants comprise in their genome at least one white rust resistance gene genetically linked to a genomic nucleic acid sequence comprised in said genome and represented by SEQ ID No. 1 or SEQ ID No. 2.

The sequences of SEQ ID No. 1 and SEQ ID No. 2 are genetically linked to white rust resistances genes, or formulated differently, SEQ ID No .1 and SEQ ID No. 2 are molecular markers indicative for the presence of white rust resistance genes. SEQ ID No. 1 and SEQ ID No. 2 can be obtained by submitting a sample comprising genomic DNA of a white rust resistant plant of the genus Chrysanthemum to a restriction digestion with the restriction enzymes Mse 1 and EcoRl optionally in combination a nucleic acid amplification using primers pairs developed based on the sequences provided herein.

Although detecting the presence of SEQ ID No. 1 or SEQ ID No. 2 is sufficient to establish whether a plant of the genus Chrysanthemum is resistant to white rust, the resistance can additionally be confirmed by a disease assay such as the disease assay outlined below. A disease assay can be conducted on cuttings or small plants inside closed plastic containers 46.5 cm length x 26.2 cm width x 26.0 cm height using a glass plate cover. White rust infected whole leaves fixed to the glass plate using 1 % agar as adhesive can be used as an inoculum. Because white rust requires a high relative humidity and a water film on the leaves, the small plants or cuttings, the inner sides of the plastic container and the cover are preferably fogged with demineralized water in combination with approximately 1 cm of demineralized water at the bottom of the plastic container. After preparing the experimental setup, the containers are placed in a dark growth chamber at room temperature for two days being followed by a period of 16 hours exposure to fluorescent light. Generally, disease symptoms can be assayed 21 to 28 days post infection. Plants are scored according to a scale of 1 (infection) to 9 (no infected) wherein a scores of 1-3 indicate the plant as being susceptible, 4-6 indicates the plant as being intermediate resistant and 7-9 indicates the plant as being resistant.

The present plants are preferably a cut Chrysanthemum plant or a pot Chrysanthemum plant. Cut Chrysanthemum plants and pot Chrysanthemum plants are also designated in the art as cut flowers and potted plants, respectively. Sometimes, also reference is made to garden Chrysanthemums being a garden proof version of a pot Chrysanthemum plant.

According to a preferred embodiment of this first aspect of the invention, the present plants belonging to the genus Chrysanthemum are selected from the group consisting of Chrysanthemum x morifolium\ Chrysanthemum x grandiflorum\ Chrysanthemum x rubellum\ Chrysanthemum aboliniv, Chrysanthemum achillaea L. \ Chrysanthemum alabasicum\ Chrysanthemum brachyanthum\ Chrysanthemum carinatum\ Chrysanthemum chalchingolicum\ Chrysanthemum cinerariifolium\ Chrysanthemum coccineum\ Chrysanthemum coreanum; Chrysanthemum coronarium\ Chrysanthemum decaisneanum\ Chrysanthemum delavayanum\ Chrysanthemum dichrum\ Chrysanthemum fastigiatum', Chrysanthemum frutescens;

Chrysanthemum gracile', Chrysanthemum gruboviv, Chrysanthemum horaimontanum\ Chrysanthemum hypoleucum\ Chrysanthemum indicum L.; Chrysanthemum junnanicum\ Chrysanthemum kinokuniense', Chrysanthemum kokanicum\ Chrysanthemum konoanum\ Crysanthemum majus', Chrysanthemum marginatum', Chrysanthemum mawei', Chrysanthemum maximum L. \ Chrysanthemum miyatojimense', Chrysanthemum morifolium\ Chrysanthemum multifidum', Chrysanthemum nitidum\ Chrysanthemum parvifolium\ Chrysanthemum przewalskiv, Chrysanthemum purpureiflorum\ Chrysanthemum ramosum\ Chrysanthemum rhombifolium\ Chrysanthemum roborowskii', Chrysanthemum segetum\ Chrysanthemum shihchuanum\ Chrysanthemum shimotomaii', Chrysanthemum trilobatum\ Chrysanthemum tripinnatisectum\ Chrysanthemum vestitum\ Chrysanthemum vulgare (L.)\ Chrysanthemum yoshinyanthemum\ and Chrysanthemum zawadskii.

According to another preferred embodiment of this first aspect of the present invention, the causative pathogen causing the present white rust disease is Puccinia horiana. Puccinia horiana is an autoecious rust. The bicellular teliospores germinate in situ to produce unicellular basidiospores which are dispersed in air currents. No other spores are known. High humidity, and a film of moisture, appear to be necessary for the germination of both teliospores and basidiospores. Teliospores are capable of germination as soon as they are mature; germination and discharge of basidiospores occur between 4°C and 23 °C and, at an optimum temperature of 17°C, discharge of basidiospores is observed within 3 hours. Basidiospores can germinate over a wide temperature range and, at 17-24°C, either surface of the leaf may be penetrated within 2 hours. Thus, only 5 hours of wetness is sufficient for a new infection to become established.

Within the leaf, abundant, hyaline, intercellular hyphae are produced with intracellular haustoria. The incubation period is normally 7-10 days, but short periods of high temperatures (over 30°C) can prolong the period to 8 weeks.

Following infection, pale-green to yellow spots, up to 5 mm in diameter, develop on the upper surface of leaves. The centres of these spots become brown and necrotic with aging. On the corresponding lower surface, raised, buff or pinkish, waxy pustules (telia) are found. As the spots on the upper surface become sunken, these pustules become quite prominent and turn whitish when basidiospores are produced. Telia are occasionally found on the upper leaf surface. Severely attacked leaves wilt, hang down the stem and gradually dry up completely.

According to yet another preferred embodiment of this first aspect, the present invention relates to plants having a resistance to white rust substantially similar to, or equivalent with, the resistance to white rust of a Chrysanthemum plant deposited under number NCIMB 42455. These plants can be readily identified by comparing white rust disease resistance, for example using a disease assay as described herein although other know white rust disease assays can be used. A Chrysanthemum plant deposited under number NCIMB 42455 can be obtained through the National Collection of Industrial, Food and Marine Bacteria (NCIMB), Ferguson Building, Craibstone Estate, Bucksburn, Aberdeen AB21 9YA, United Kingdom.

According to a particularly preferred embodiment of this first aspect, the present plants have a resistance to white rust identical to the white rust resistance found in a Chrysanthemum plant deposited under number NCIMB 42455. Especially preferred are plants comprising at least one white rust resistance gene, preferably at least two white rust resistance genes, derived from a Chrysanthemum plant deposited under number NCIMB 42455 wherein the presence of said white rust resistance gene or genes is indicated by the presence of SEQ ID No. 1 or SEQ ID No. 2 in the genome of said plant. Formulated differently, SEQ ID No. 1 or SEQ ID No. 2 are molecular, or genomic, markers indicative for, thus genetically linked with, the present resistance genes which can, for example, be found in NCIMB 42455.

According to a yet another particularly preferred embodiment of this first aspect, the present plants comprise in their genome at least two white rust resistance genes, the first white rust resistance gene is genetically linked to a genomic nucleic acid sequence comprised in said plant genome represented by SEQ ID No. 1 and the second white rust resistance gene is genetically linked to a genomic nucleic acid sequence comprised in said plant genome represented by SEQ ID No. 2.

According to a most preferred embodiment of the first aspect, the present invention relates to a Chrysanthemum x morifolium plant, wherein the plant is resistant to the white rust pathogen Puccinia horiana and the white rust resistance is encoded by a first resistance gene genetically linked to SEQ ID No. 1 and/or a second resistance gene genetically linked to SEQ ID No. 2.

Considering the importance of white rust resistant genetic sources in the art, such as the present plants, the present invention, according to a second aspect, relates to seeds, plant parts or plant cells of the present plants. The present seeds, plant parts or plant cells comprise in their genome SEQ ID No. 1 and/or SEQ ID No. 2, preferably SEQ ID No. 1 and SEQ ID No. 2 and are, accordingly, capable of providing, or cultivated into, plants being resistant to white rust and especially white rust caused by an infection with Puccinia horiana.

According to a third aspect, the present invention also relates to progeny of the present Chrysanthemum plants. Progeny of the present plants can be readily identified by establishing the presence of SEQ ID No. 1 and/or SEQ ID No. 2, preferably SEQ ID No. 1 and SEQ ID No. 2, in their genome.

According to a fourth aspect, the present invention relates to the use of SEQ ID No. 1 or SEQ ID No. 2 for identifying a white rust resistant Chrysanthemum plant. Suitable methods, based on SEQ ID No. 1 or SEQ ID No. 2, for identifying such plant are generally known in the art such as methods based on nucleic acid amplification of genomic DNA and subsequent visualisation of amplification fragments although other techniques can be envisaged such as techniques based on hybridisation.

SEQUENCE LISTING <110> FIDES B.V. <12 0> WHITE RUST RESISTANT CHRYSANTHEMUM PLANTS <130> 4/2SH44/14 <160> 2 <170> BiSSAP 1.3

<210> 1 <211> 192 <212> DNA <213> Chrysanthemum <genus> <22 0> <223> Sequence around 29TgR2 <400> 1 ttaactcaaa aatatgacta caaatcaatt ttcaggactt tttttcgata cttccctctt 60 tggtaccggt accgtattag tggtaccgat tttttttggg ctcaattcat ggtacaggca 120 ccgtaccgtg tattgggagt cggtaccgtt tcgatacggt accggtacgg ttccgattcg 180 ataccggaat tc 192

<210> 2 <211> 180 <212> DNA <213> Chrysanthemum <genus> <22 0> <223> Sequence around 24HslRl <400> 2 gaattcctat acgaaggttt tgtagatgtg tctccgagcg agtttgatcc taactcacga 60 ctagtaattt atgtccataa aaccgataac ttgaacattc cctcttgttc ttgtagatgg 120 ggatgacttc actgagtctc cattcttctg gcatcttatc actggaaaaa atcttgttaa 180

CLAUSESS 1. Plant belonging to the genus Chrysanthemum, said plant is resistant to white rust and said plant comprises in its genome at least one white rust resistance gene, said white rust resistance gene is genetically linked to a genomic nucleic acid sequence comprised in said genome represented by SEQ ID No. 1 or SEQ ID No. 2. 2. Pant according to clause 1, wherein said plant is a cut Chrysanthemum or said plant is a pot Chrysanthemum. 3. Plant according to clause 1 or clause 2, wherein said plant is selected from the group consisting of Chrysanthemum x morifolium\ Chrysanthemum x grandiflorum\ Chrysanthemum x rubellum\ Chrysanthemum aboliniv, Chrysanthemum achillaea L. \ Chrysanthemum alabasicum\ Chrysanthemum brachyanthum\ Chrysanthemum carinatum\ Chrysanthemum chalchingolicum\ Chrysanthemum cinerariifolium\ Chrysanthemum coccineum\ Chrysanthemum coreanum; Chrysanthemum coronarium\ Chrysanthemum decaisneanum\ Chrysanthemum delavayanum\ Chrysanthemum dichrum\ Chrysanthemum fastigiatum', Chrysanthemum frutescens; Chrysanthemum gracile; Chrysanthemum gruboviv, Chrysanthemum horaimontanum\ Chrysanthemum hypoleucum\ Chrysanthemum indicum L.; Chrysanthemum junnanicum\ Chrysanthemum kinokuniense; Chrysanthemum kokanicum\ Chrysanthemum konoanum\ Crysanthemum majus', Chrysanthemum marginatum', Chrysanthemum mawev, Chrysanthemum maximum L.; Chrysanthemum miyatojimense', Chrysanthemum morifolium\ Chrysanthemum multifidum; Chrysanthemum nitidum; Chrysanthemum parvifolium; Chrysanthemum przewalskii', Chrysanthemum purpureiflorum\ Chrysanthemum ramosum\ Chrysanthemum rhombifolium\ Chrysanthemum roborowskiv, Chrysanthemum segetum\ Chrysanthemum shihchuanum; Chrysanthemum shimotomaiv, Chrysanthemum trilobatum\ Chrysanthemum tripinnatisectum\ Chrysanthemum vestitum\ Chrysanthemum vulgare (L.)\ Chrysanthemum yoshinyanthemum\ and Chrysanthemum zawadskii. 4. Plant according to any of the clauses 1 to 3, wherein the causative pathogen of said white rust is Puccinia horiana. 5. Plant according to any of the clauses 1 to 4, wherein said plant has a resistance to white rust substantially similar to, or equivalent with, the resistance to white rust of a Chrysanthemum plant deposited under number NCIMB 42455. 6. Plant according to clause 5, wherein said plant has a resistance to white rust found in a Chrysanthemum plant deposited under number NCIMB 42455. 7. Plant according to any of the clauses 1 to 6, wherein said plant comprises in its genome at least two white rust resistance genes, the first white rust resistance gene is genetically linked to a genomic nucleic acid sequence comprised in said plant genome represented by SEQ ID No. 1 and the second white rust resistance gene is genetically linked to a genomic nucleic acid sequence comprised in said plant genome represented by SEQ ID No. 2. 8. Plant according to any of the clauses 1 to 7, said plant comprises at least one white rust resistance gene derived from a Chrysanthemum plant deposited under number NCIMB 42455 wherein the presence of said white rust resistance gene is indicated by the presence of SEQ ID No. 1 or SEQ ID No. 2 in the genome of said plant. 9. Plant according to any of the clauses 1 to 7, said plant comprises at least two white rust resistance genes derived from a Chrysanthemum plant deposited under number NCIMB 42455 wherein the presence of said white rust resistance genes is indicated by the presence of SEQ ID No. 1 and SEQ ID No. 2 in the genome of said plant. 10. Plant according to any of the clauses 1 to 9, wherein said plant is a Chrysanthemum x morifolium plant, said plant is resistant to the white rust pathogen Puccinia horiana and said resistance is encoded by a first resistance gene genetically linked to SEQ ID No. 1 and/or a second resistance gene genetically linked to SEQ ID No. 2. 11. Seeds, plant parts or plant cells of a Chrysanthemum plant according to any of the clauses 1 to 10. 12. Progeny of a Chrysanthemum plant according to any of the clauses 1 to 10. 13. Use of SEQ ID No. 1 and/or SEQ ID No. 2 for identifying a white rust resistant Chrysanthemum plant.

Claims

A plant of the genus Chrysanthemum, wherein said plant is resistant to white rust and said plant comprises in its genome at least one white rust resistance gene, said white rust resistance gene is genetically linked to a genomic nucleic acid sequence included in the said genome and represented by SEQ ID NO. 1 or SEQ ID No. 2.

The plant of claim 1, wherein said plant is a cut chrysanthemum plant or a pot chrysanthemum plant.

A plant according to claim 1 or claim 2, wherein said plant is selected from the group consisting of Chrysanthemum x morifolium, Chrysanthemum x grandiflorum, Chrysanthemum x rubellum, Chrysanthemum aboliniv, Chrysanthemum achillaea L. \ Chrysanthemum alabasicum ', Chrysanthemum brachyanthum ', Chrysanthemum carinatum', Chrysanthemum chalchingolicum ', Chrysanthemum cinerariifolium', Chrysanthemum coccineum ', Chrysanthemum coreanum; Chrysanthemum coronarium ', Chrysanthemum decaisneanum', Chrysanthemum delavayanum ', Chrysanthemum dichrum', Chrysanthemum fastigiatum ', Chrysanthemum frutescens; Chrysanthemum gracile; Chrysanthemum gruboviv, Chrysanthemum horaimontanum, Chrysanthemum hypoleucum, Chrysanthemum indicum L .; Chrysanthemum junnanicum \ Chrysanthemum kinokuniense; Chrysanthemum kokanicum ', Chrysanthemum konoanum', Crysanthemum majus', Chrysanthemum marginatum ', Chrysanthemum mawei', Chrysanthemum maximum L .; Chrysanthemum miyatojimense; Chrysanthemum morifolium; Chrysanthemum multifidum ', Chrysanthemum nitidum', Chrysanthemum parvifolium ', Chrysanthemum przewalskii', Chrysanthemum purpureiflorum ', Chrysanthemum ramosum', Chrysanthemum rhombifolium ', Chrysanthemum roborowskii', Chum santhemum seget; Chrysanthemum shihchuanum ', Chrysanthemum shimotomaii', Chrysanthemum trilobatum ', Chrysanthemum tripinnatisectum', Chrysanthemum vestitum ', Chrysanthemum vulgare (L.j', Chrysanthemum yoshinyanthemum ', and Chrysanthemum zawadskii.

The plant of any one of claims 1 to 3, wherein the causative pathogen of said white rust is Puccinia horiana.

The plant of any one of claims 1 to 4, wherein said plant has a white rust resistance substantially similar to, or equivalent to, the white rust resistance of a chrysanthemum plant deposited under number NCIMB 42455.

The plant of claim 5, wherein said plant has a white rust resistance found in a chrysanthemum plant deposited under number NCIMB 42455.

The plant of any one of claims 1 to 6, wherein said plant comprises in its genome at least two white rust resistance genes, the first white rust resistance gene is genetically linked to a genomic nucleic acid contained by said plant and represented by SEQ ID NO. 1 and the second white rust resistance gene is genetically linked to a genomic nucleic acid contained by said plant and represented by SEQ ID NO. 2.

The plant of any one of claims 1 to 7, wherein said plant comprises at least one white rust resistance gene obtained from a chrysanthemum plant deposited under number NCIMB 42455 wherein the presence of said white rust resistance gene is indicated by the presence from SEQ ID No. 1 or SEQ ID No. 2 in the genome of the said plant.

The plant of any one of claims 1 to 7, wherein said plant comprises at least two white rust resistance genes obtained from a chrysanthemum plant deposited under number NCIMB 42455 wherein the presence of said white rust resistance genes is indicated by the presence from SEQ ID No. 1 and SEQ ID No. 2 in the genome of the said plant.

The plant of any one of claims 1 to 9, wherein said plant is a Chrysanthemum x morifolium plant, said plant is resistant to the white rust pathogen Puccinia horiana and said resistance is encoded by a first resistance genetically linked with SEQ ID No. 1 and / or a second resistance gene genetically linked to SEQ ID NO. 2.

Seeds, plant parts or plant cells of a chrysanthemum plant according to any of claims 1 to 10.

12. Descendants of a chrysanthemum plant according to any of claims 1 to 10.

13. Use of SEQ ID No. 1 and / or SEQ ID No. 2 for identifying a white rust-resistant chrysanthemum plant.