spinach plant

Abstract

The present invention aims to provide spinach plants that are resistant to downy mildew. [Solution] The present invention provides a spinach plant including a spinach plant or its progeny line identified by accession number FERM BP-22502 or FERM BP-22503. The spinach plant of the present invention exhibits resistance to downy mildew, preferably to one or more selected from downy mildew races Pfs2, Pfs4, Pfs5, Pfs6, Pfs7, Pfs10, Pfs11, Pfs12, Pfs13, Pfs14, Pfs15, Pfs16, Pfs17, Pfs18, and Pfs19.

Description

Technical Field

[0001] The present invention relates to spinach plants.

Background Art

[0002] Spinach is positioned as an "officially designated vegetable" important for the national life, together with cabbage, radish, tomato, etc., and has become an indispensable vegetable in today's diet. In recent years, mainly in Europe and the United States, the baby leaf market, which can be easily eaten in salads, has been rapidly expanding, and it is a vegetable with high demand worldwide.

[0003] One of the diseases threatening spinach cultivation is downy mildew, which has become a serious problem worldwide. Downy mildew is caused by the filamentous fungus Peronospora farinosa (synonym Peronospora effusa). Once it occurs, it spreads rapidly, causing significant damage to yield and quality.

[0004] For the control of downy mildew, tillage and chemical measures using agricultural chemicals have been taken. However, from the perspectives of environmental and food safety, cultivation labor, and cost, there are high expectations for resistant varieties.

[0005] Although the development of resistant varieties has been promoted so far, downy mildew has extremely rapid race differentiation, and new races capable of infecting resistant varieties have emerged one after another, and cases where disease spreads in varieties that should have resistance have occurred repeatedly (Non-Patent Document 1).

Prior Art Documents

Non-Patent Documents

[0006]

Non-Patent Document 1

[0007] In view of the above-mentioned problems, the present invention aims to provide a spinach plant that is resistant to downy mildew. [Means for solving the problem]

[0008] The present invention provides the following: [1] Spinach plants, including spinach plants or their descendants, identified by accession number FERM BP-22502 or FERM BP-22503. [2] Spinach plants described in [1] that exhibit resistance to downy mildew. [3] A spinach plant as described in [1] that exhibits resistance to one or more downy mildew races selected from Pfs2, Pfs4, Pfs5, Pfs6, Pfs7, Pfs10, Pfs11, Pfs12, Pfs13, Pfs14, Pfs15, Pfs16, Pfs17, Pfs18, and Pfs19. [4] A first-generation hybrid (F1 hybrid) spinach plant as described in any one of the items [1] to [3]. [5] A spinach plant, either as a plant body or a part thereof, as described in any one of items [1] to [4]. [6] A spinach plant that is a seed, as described in any one of items [1] to [5]. A self-pollination process for spinach plants as described in any one of items [7], [1] to [6], or A hybridization process involving crossing a spinach plant described in any one of items [1] to [6] with another spinach plant. A method for producing spinach plants, including [the specified ingredient]. [8] A method for producing spinach plants according to [7], comprising a seed collection step for collecting seeds. [Effects of the Invention]

[0009] The present invention provides a novel spinach plant. Since the spinach plant of the present invention exhibits high resistance to downy mildew, it is expected that the occurrence of downy mildew in spinach production can be suppressed, thereby stabilizing quality, yield, and ultimately production. [Modes for carrying out the invention]

[0010] [1. Spinach plant] The spinach plants of the present invention include spinach plants or their progeny lines identified by accession number FERM BP-22502 or FERM BP-22503.

[0011] [1.1 Strains and varieties] In this specification, the spinach plant refers to the Spinach species (Spinacia oleracea L.) of the genus Spinach in the subfamily Chenopodiaceae of the family Amaranthaceae. Origin, variety, and sowing time (autumn sowing, spring sowing) are not particularly limited. "Spinach plant" usually refers to "cultivated spinach," but may also be a hybrid of "wild spinach" (e.g., Spinach turkestanica, Spinach tetrandra). Cultivated spinach is a spinach variety that has been artificially selected and bred for characteristics such as taste, shape, yield, ease of cultivation, and seed productivity. Cultivated spinach is superior to wild spinach in terms of characteristics required for agricultural use, such as germination, reproductive traits, and shape. In the case of hybrids with wild species, it is preferable that the characteristics as an agricultural crop are the same as or similar to those of cultivated spinach. The spinach plant may be an open-pollinated variety, an F1 variety, a parent line of an F1 variety, or a breeding line.

[0012] [1.2 Plant] The spinach plant may be the plant body or a part thereof. In this specification, "plant body" includes the cells or tissues of the plant body, and specifically includes leaves, stems, roots, flowers, ovaries, anthers, pollen, seeds, etc. Of these, it is preferable that at least edible parts (e.g., leaves, stems, and combinations thereof) or seeds are included.

[0013] [1.3 Resistance to beet disease] Spinach plants possess downy mildew resistance. Downy mildew is a disease caused by fungi belonging to the Peronosporaceae family. The main pathogen of spinach downy mildew is Pfs (Peronospora farinosa f.sp.spinaciae). When infected, pale yellow lesions with indistinct borders appear on the upper surface of the leaves. As the disease progresses, grayish-purple spores are formed on the underside of the lesions, leading to leaf death. Pfs undergoes extremely rapid race differentiation, and new races capable of infecting resistant varieties are constantly emerging, resulting in repeated cases of disease spreading to varieties that should be resistant. The IWGP (International Working Group of Peronospora) monitors the occurrence and spread of downy mildew in major production areas and officially recognizes new races that are expected to break down conventional downy mildew-resistant varieties and spread further. As a result, 20 races have been certified to date (https: / / www.plantum.nl / nieuws / denomination-of-pe-20-a-new-race-of-downy-mildew-in-spinach / ).

[0014] In this specification, downy mildew resistance can mean any of the following: no occurrence of disease due to infection by the downy mildew pathogen, cessation of disease progression once it has occurred, or inhibition of disease progression. Furthermore, the degree of resistance is not particularly limited and includes not only "resistance" in which no disease is observed in either the cotyledons or true leaves, but also "moderate resistance" in which only slight disease is observed in the cotyledons.

[0015] Resistance may be resistance to at least one of downy mildew races 1 to 20, or resistance to multiple races. Preferably, the resistance is to one or more, two or more, three or more, four or more, five or more, six or more, seven or more, eight or more, nine or more, ten or more, eleven or more, twelve or more, thirteen or more, or all of the races selected from the group consisting of Pfs2, Pfs4, Pfs5, Pfs6, Pfs7, Pfs10, Pfs11, Pfs12, Pfs13, Pfs14, Pfs15, Pfs16, Pfs17, Pfs18, and Pfs19. It is more preferable that the resistance is a combination that includes resistance to Pfs17. In this specification, a downy mildew-susceptible spinach plant is a spinach plant that does not show resistance to any downy mildew race.

[0016] The downy mildew resistance of spinach plants can be confirmed according to the race inoculation test described below to investigate downy mildew resistance.

[0017] Sow the target spinach seeds in pots filled with growing medium. As an indicator of disease development, also sow seeds of a strain that shows susceptibility to the inoculated race. Grow these pots in an artificial climate chamber for about two weeks, and when the plants have two true leaves, inoculate them with a Pfs spore suspension (5 × 10 4 Inoculate with a spray of conidia ( / mL). Immediately after inoculation, place the potted seedlings in a sealed container, maintain 100% humidity, and manage them in an artificial climate chamber set to a temperature of 15°C and a 12-hour day length. 7-10 days after inoculation, after thoroughly checking for disease development in the control group, determine the resistance and susceptibility of each individual plant. Plants showing disease with the appearance of hyphae and spores on the cotyledons or true leaves are classified as susceptible, plants showing no disease in either the cotyledons or true leaves are classified as resistant, and plants showing slight disease only in the cotyledons but no disease in the true leaves are classified as moderately resistant.

[0018] Each race of downy mildew can be obtained from The University of Arkansas (Dr. Jim Correll) and Naktuinbouw. In addition, for race discrimination of downy mildew, differential sets of discriminant varieties that show different resistance patterns for each race have been organized and can be used. The discriminant varieties are available from Naktuinbouw.

[0019] Table 1 shows the known resistance of spinach plants reported for each race. In the table, "R" means resistant, "(R)" means moderately resistant, and "S" means susceptible.

[0020]

Table 1

[0021] [1.4 Deposited Spinach Plants] The spinach plants of the present invention are preferably spinach plants identified by accession numbers FERM BP-22502 and FERM BP-22503.

[0022] The above spinach plants are also referred to as 23.1301 and 23.1305 respectively in this specification, and are internationally deposited based on the Budapest Treaty with accession numbers FERM BP-22502 and FERM BP-22503 at the Patent Biological Depositary Center, National Institute of Technology and Evaluation (NITE-IPOD: Room 120, 2-5-8 Kazusa Kamashima, Kisarazu City, Chiba Prefecture 292-0818, Japan) on June 20, 2024.

[0023] The spinach plants identified under accession numbers FERM BP-22502 and FERM BP-22503 possess, for example, the morphological and physiological characteristics shown in Table 2. These characteristics are based on the results of cultivation trials conducted in Japan in 2024. The morphological and physiological characteristics in Table 2 are based on the spinach species selection criteria (issued April 2022, http: / / www.maff.go.jp / j / shokusan / hinshu / info / kijun / 1605.pdf) published by the Ministry of Agriculture, Forestry and Fisheries (MAFF).

[0024] [Table 2]

[0025] Spinach plants identified by accession numbers FERM BP-22502 or FERM BP-22503 are resistant to downy mildew races Pfs2, Pfs4, Pfs5, Pfs6, Pfs7, Pfs10, Pfs11, Pfs12, Pfs13, Pfs14, Pfs15, Pfs16, Pfs17, Pfs18, and Pfs19.

[0026] [1.5 Progeny lineage] The spinach plants of the present invention may be progeny lines of spinach plants specified by accession number FERM BP-22502 or FERM BP-22503. The progeny lines may be progeny lines resulting from crosses between spinach plants specified by FERM BP-22502 or FERM BP-22503, or with other spinach plants (either cultivated spinach or wild spinach), and in the latter case, it is preferable that they are first-generation hybrids. It is preferable that the downy mildew resistance possessed by the progeny lines is equivalent to that of the spinach plants identified by the parent plants FERM BP-22502 or FERM BP-22503 (for example, resistance to one or more selected from the group consisting of Pfs2, Pfs4, Pfs5, Pfs6, Pfs7, Pfs10, Pfs11, Pfs12, Pfs13, Pfs14, Pfs15, Pfs16, Pfs17, Pfs18, and Pfs19, especially combinations including Pfs17). Furthermore, the progeny may possess downy mildew resistance to races different from those identified in FERM BP-22502 or FERM BP-22503 (e.g., resistance to Pfs1, Pfs3, Pfs8, Pfs9, and Pfs20).

[0027] The progeny lines are preferably substantially similar in trait to the spinach plants identified in FERM BP-22502 or FERM BP-22503. For example, they have at least one of the morphological and physiological features shown in Table 2, such as two or more, three or more, four or more, five or more, six or more, seven or more, eight or more, nine or more, ten or more, eleven or more, twelve or more, thirteen or more, fourteen or more, fifteen or more, sixteen or more, seventeen or more, or all of the same trait.

[0028] The progeny may have substantially the same genetic characteristics as the spinach plants identified by FERM BP-22502 or FERM BP-22503. Examples of genetic characteristics include gene markers (e.g., SNPs, AFLPs, RFLPs, CAPS, SCAR markers) and nucleotide sequences, with concordance rates of, for example, 5% or more, 10% or more, 20% or more, 30% or more, 40% or more, 50% or more, 60% or more, 70% or more, 80% or more, 90% or more, 95% or more, 99% or more, or 100% or more.

[0029] The progeny may have genes introduced from different or the same species. The introduction may be artificial or natural, and known genetic engineering techniques can be used. Furthermore, the progeny may be doubled haploid plants or haploid plants.

[0030] [2. Manufacturing method] Examples of methods for producing spinach plants according to the present invention (creation method, cultivation method, or production method) include a method that includes a self-pollination step in which the spinach plants are self-pollinated, a method that includes a hybridization step in which the spinach plants are crossbred with other spinach plants, and a method that further includes a self-pollination step or a hybridization step and a selection step in which spinach plants having downy mildew resistance are selected after these steps. By repeatedly performing the self-pollination step or hybridization step and the step of selecting spinach plants having resistance, it is possible to cultivate and mass-produce spinach plants that have downy mildew resistance.

[0031] The crossbreeding and self-pollination processes may be repeated two or more times. For example, a method may include a first crossbreeding process in which the spinach plant of the present invention is crossed with any spinach plant, and a second crossbreeding process in which the first generation hybrid obtained in the first crossbreeding process is self-pollinated, backcrossed, or crossed with a spinach plant different from the line used in the first crossbreeding process. A selection process may be performed between each process as needed.

[0032] The production of spinach plants preferably includes a seed collection process. This allows for the efficient production of spinach plants using seeds.

[0033] Furthermore, the spinach plant of the present invention can also be produced by regenerating from a part of the spinach plant body. Regeneration can be achieved, for example, by culturing cells, tissues, or organs that constitute the spinach plant body, or protoplasts prepared from these. In addition, if necessary, treatments such as the introduction of heterologous or homologous genes or chromosome doubling may be performed. [Examples]

[0034] [Example 1] We bred deposited spinach plants and evaluated their morphological and physiological characteristics, as well as their resistance to downy mildew.

[0035] (1) Breeding of deposited lines In 2020, wild spinach was obtained from the Centre for Genetic Resources in the Netherlands, and its resistance to downy mildew was evaluated. From these, lines showing resistance to Pfs17 were selected and crossed with a spinach line owned by Tohoku Co., Ltd. that was not resistant to Pfs17. Individuals showing resistance using Pfs17 as an indicator were selected, and backcrossing and self-pollination were repeated multiple times to create parent lines 23.1301 and 23.1305 of spinach with fixed downy mildew resistance. 23.1301 and 23.1305 are F1 varieties obtained by crossing the above parent lines with a downy mildew-susceptible line owned by Tohoku Co., Ltd., and the resistance patterns of the parent lines are identical to those of 23.1301 and 23.1305, respectively.

[0036] The obtained 23.1301 and 23.1305 were deposited with NITE-IPOD under accession numbers FERM BP-22502 and FERM BP-22503, respectively.

[0037] (2) Evaluation of traits of deposited strains The characteristics and traits of the deposited lines were evaluated according to the spinach species evaluation criteria established by MAFF. The results are shown in Tables 3-1 and 3-2.

[0038] [Table 3-1]

[0039] [Table 3-2]

[0040] (3) Evaluation of downy mildew resistance of deposited strains Race inoculation tests to investigate the downy mildew resistance of deposited strains were conducted using the method described above. The evaluation results for each downy mildew race are shown in Table 4. In the table, "R" indicates resistance, "(R)" indicates moderate resistance, and "S" indicates susceptibility. "nt" indicates not tested. Each downy mildew race was obtained from within Japan, The University of Arkansas (Dr. Jim Correll), and Naktuinbouw.

[0041] [Table 4]

Claims

1. Spinach plants, including spinach plants or their descendants, identified by accession number FERM BP-22502 or accession number FERM BP-22503.

2. The spinach plant according to claim 1, exhibiting resistance to downy mildew.

3. The spinach plant according to claim 1, which exhibits resistance to one or more downy mildew races selected from Pfs2, Pfs4, Pfs5, Pfs6, Pfs7, Pfs10, Pfs11, Pfs12, Pfs13, Pfs14, Pfs15, Pfs16, Pfs17, Pfs18, and Pfs19.

4. A spinach plant according to any one of claims 1 to 3, which is a first-generation hybrid (F1 hybrid).

5. A spinach plant according to any one of claims 1 to 3, which is a plant body or a part thereof.

6. A spinach plant according to any one of claims 1 to 3, which is a seed.

7. A self-propagation process for self-propagating spinach plants according to any one of claims 1 to 3, A crossbreeding step of crossbreeding a spinach plant according to any one of claims 1 to 3 with another spinach plant. A method for producing spinach plants, including [the specified ingredient].

8. A method for producing spinach plants according to claim 7, further comprising a seed collection step for collecting seeds.

Images