Английская Википедия:Hyaloperonospora
Шаблон:Short description Шаблон:Automatic taxobox
Hyaloperonospora is a genus of oomycete, obligate, plant pathogens that was originally considered to be part of Peronospora.[1] Species in this group produce a disease called downy mildew and can infect many important crops.[1] From the 19 downy mildew producing genera, Hyaloperonospora has been grouped with Perofascia in the brassicolous downy mildews.[1] In the group of downy mildews, Hyaloperonospora is the third biggest genus.[1] The most famous species in the genus is the Hyaloperonospora parasitica, or also known as Hyaloperonospora arabidopsis.[2] This species has become a model organism from its ability to infect the model plant Arabidopsis thaliana.[2] It is used to study plant-pathogen interactions, and is currently the only Hyaloperonospora species that has an assembled genome.[2]
History
In 2002, Hyaloperonospora was discovered and described by Constantinescu, O. and Fatehi,J. using morphological and molecular characteristics.[3] Later, Göker et al., also used molecular phylogenetic techniques showing that the group was different enough from the other Peronospora species to be its own taxon.[4] Hyaloperonospora along with Perofascia were the first downy mildews described using their molecular phylogenies.[1]
Habitat and ecology
Hyaloperonospora can be found on plants from about 20 different tribes of Brassicaceae.[1] They can generally be found anywhere their host plant grows, due to human transport from seed trade.[1] Hyaloperonospora parasitica is unlike most other species in the family in that it has a very wide host range, infecting a variety of cropsШаблон:Citation needed. Another important interaction is with Hyaloperonospora brassicae, which also has a wider host range infecting many Brassica speciesШаблон:Citation needed.
General form and structure
Hyaloperonospora differs from Perofascia in that its sporangiophores are tree-like, its haustoria are lobate to globose, and the walls of its oospores are relatively thinner.[1]
The life history does not differ from that of Peronospora, the genus that Hyaloperonospora species used to be classified underШаблон:Citation needed. It begins as sporangia, which are small spore-like structure, and when it lands next to a leaf stoma, it germinates a germ-tube.[5] The germ tube enters the leaf cell creating a haustorium, which allows the mould the uptake nutrients from the leaf.[5] The mould will continue to grow, with hyphae extending into the leaf's intercellular space.[5] This invasion kills some of the leaf cells and the leaf will develop a lesion followed by necrosis.[5] If the conditions are favourable, the mould will undergo asexual reproduction and produce a tree of sporangiophores out of the leaf.[5] The sporangiophores will produce conidia that can be dispersed by the wind to another plant.[5] If the conditions in the leaf were unfavourable, the mould can undergo sexual reproduction and produce haploid antheridia and haploid oogonia through meiosis.[5] These two structures are the only non-diploid stages of the Hyaloperonospora.[5] The antheridia will fuse to the oogonia inducing plasmogamy followed by karyogamy to form diploid oospores.[5] The oospores will then be dispersed through the wind to infect more plants.[5]
Practical importance
Hyaloperonospora arabidopsis infects the model plant Arabidopsis thaliana, and by association has become a model pathogen for studying plant-pathogen interactions.[2] Studying these interactions should give us insight into how we can more effectively protect our crops from deadly eukaryotic pathogens. It is also used as a model in the Arabidopsis eFP Browser as one of the nine biotic stresses.[6]
Genomics and genetics
The Hyaloperonospora arabidopsis genome was first sequenced and assembled in 2008 using Sanger and Illumina sequencing, by Baxter et al.[7] They reported a genome size of 78 Mb with 9.5x coverage of the nuclear genome and did not assemble the mitochondrial genome.[7] They also found that 42% of the genome consisted of repetitive elements.[7] 14,543 protein coding genes were predicted using a program to detect gene models.[7]
In 2015, two more isolates of Hyaloperonospora arabidopsis were sequenced using Illumina HiSeq with 90x coverage, and reported genome sizes of 70 Mb and 74 MbШаблон:Citation needed.
Species include
- Hyaloperonospora arabidopsidis (Gäum.) Göker, Voglmayr, Riethm., Weiss & Oberw., 2003
- Hyaloperonospora brassicae (Gäum.) Göker, Voglmayr, Riethm., Weiss & Oberw., 2003
- Hyaloperonospora parasitica (Pers.) Constant., 2002
- Hyaloperonospora drabae
- Hyaloperonospora floerkeae (Kellerm.) Constant. 2002
- Hyaloperonospora camelinae
- Hyaloperonospora dentariae (Rabenh.) Voglmayr 2013
- Hyaloperonospora isatidis
- Hyaloperonospora erophilae
- Hyaloperonospora cardamines-enneaphyllos Voglmayr 2013
- Hyaloperonospora cheiranthi
- Hyaloperonospora arabidis-alpinae
- Hyaloperonospora sisymbrii-loeselii
- Hyaloperonospora sisymbrii-sophiae
- Hyaloperonospora malyi (Lindtner) Voglmayr 2013
- Hyaloperonospora tribulina (Pass.) Constant. 2002
- Hyaloperonospora barbareae
- Hyaloperonospora lobulariae
- Hyaloperonospora berteroae
- Hyaloperonospora galligena
- Hyaloperonospora hesperidis
- Hyaloperonospora dentariae-macrophyllae
- Hyaloperonospora cardamines-laciniatae
- Hyaloperonospora rorippae-islandicae
- Hyaloperonospora lunariae
- Hyaloperonospora cochleariae
- Hyaloperonospora lepidii-perfoliati (Savul. & Rayss) Constant. 2002
- Hyaloperonospora thlaspeos-perfoliati
- Hyaloperonospora nesliae
- Hyaloperonospora thlaspeos-arvensis
- Hyaloperonospora cardaminopsidis
- Hyaloperonospora nasturtii-aquatici
- Hyaloperonospora praecox
- Hyaloperonospora norvegica
- Hyaloperonospora niessliana (Berl.) Constant. 2002
References
Шаблон:Commons category Шаблон:Reflist
