Expression profiling of marker genes responsive to the defence-associated phytohormones salicylic acid, jasmonic acid and ethylene in Brachypodium distachyon. Issue 1 (December 2016)

• Record Type: Journal Article
• Authors: Kouzai, Yusuke; Kimura, Mamiko; Yamanaka, Yurie; Watanabe, Megumi; Matsui, Hidenori; Yamamoto, Mikihiro; Ichinose, Yuki; Toyoda, Kazuhiro; Onda, Yoshihiko; Mochida, Keiichi; Noutoshi, Yoshiteru
• Is Part Of: BMC plant biology. Volume 16:Issue 1(2016)
• Page Start: 1
• Page End: 11
• Publication Date: 2016-12
• Subjects: Brachypodium distachyon -- Phytohormone -- Salicylic acid -- Jasmonic acid -- Ethylene -- Plant disease resistance -- Defense mechanism -- Immunity system -- Marker gene; Plant molecular biology -- Periodicals; Botany -- Periodicals; 580.5
• DOI: 10.1186/s12870-016-0749-9
• Languages: English
• ISSNs: 1471-2229

Abstract

Abstract Background Brachypodium distachyon is a promising model plants for grasses. Infections ofBrachypodium by various pathogens that severely impair crop production have been reported, and the species accordingly provides an alternative platform for investigating molecular mechanisms of pathogen virulence and plant disease resistance. To date, we have a broad picture of plant immunity only inArabidopsis and rice; therefore, Brachypodium may constitute a counterpart that displays the commonality and uniqueness of defence systems among plant species. Phytohormones play key roles in plant biotic stress responses, and hormone-responsive genes are used to qualitatively and quantitatively evaluate disease resistance responses during pathogen infection. For these purposes, defence-related phytohormone marker genes expressed at time points suitable for defence-response monitoring are needed. Information about their expression profiles over time as well as their response specificity is also helpful. However, useful marker genes are still rare inBrachypodium . Results We selected 34 candidates forBrachypodium marker genes on the basis of protein-sequence similarity to known marker genes used inArabidopsis and rice.Brachypodium plants were treated with the defence-related phytohormones salicylic acid, jasmonic acid and ethylene, and their transcription levels were measured 24 and 48 h after treatment. Two genes for salicylic acid, 7 for jasmonic acid and 2 for ethylene were significantly induced at either or both time points. We then focused on 11 genes encoding pathogenesis-related (PR) 1 protein and compared their expression patterns with those ofArabidopsis and rice. Phylogenetic analysis suggested thatBrachypodium contains severalPR1 -family genes similar to rice genes. Our expression profiling revealed that regulation patterns of somePR1 genes as well as of markers identified for defence-related phytohormones are closely related to those in rice. Conclusion We propose that theBrachypodium immune hormone marker genes identified in this study will be useful to plant pathologists who useBrachypodium as a model pathosystem, because the timing of their transcriptional activation matches that of the disease resistance response. Our results usingBrachypodium also suggest that monocots share a characteristic immune system, defined as the common defence system, that is different from that of dicots.