Molecular Plant∣華中農業大學發文揭示水稻逃旱的遺傳和分子機制

2018年1月19日，Molecular Plant發表了題為「Integrative Regulation of Drought Escape through ABA Dependent and Independent Pathways in Rice」的文章。

該文章為華中農業大學熊立仲教授課題組完成。

目前對植物的抗旱已有很深入的研究，植物的抗旱包括避旱，耐旱，逃旱和復原抗旱性。而對於植物逃旱性的遺傳和分子機制目前還不清楚。

本文的研究結果證明了水稻的逃旱性是通過生殖轉變過程中的多種途徑協調調控的。即通過依賴ABA和不依賴ABA的途徑共同調控。揭示了水稻逃旱性新的機制，為作物的抗旱研究提供了新的觀點。

摘要：

在面臨缺水的情況下，許多植物形成了逃旱（DE）機制，以縮短它們的生命周期。儘管對耐旱性已進行深入的研究，但DE的遺傳和分子機制仍然不清楚。我們發現，在水稻發育早期低水分虧缺處理（LWT）可以觸發早花和減少分櫱數量。LWT誘導了ABA的積累，反過來又通過同步調節許多與開花有關的基因，反饋影響了光感知和生物鐘，從促進開花而。此外，發現一些光受體，晝夜節律組分和包括OsTOC1，Ghd7和PhyB的開花相關基因，它們以依賴ABA的方式參與LWT，而其他一些開花相關基因包括OsGI，OsELF3 ，OsPRR37和OsMADS50則參與調控不依賴於ABA的DE。此外，我們發現在LWT條件下，獨腳金內酯和OsTB1參與了的分櫱抑制，這與水稻的開花途徑無關。綜上所述，我們的研究結果提供了令人信服的證據，證明水稻中的DE，是通過生殖（開花）轉換中的多種途徑協調調節的。

Abstract：

Many plants have evolved a drought escape (DE) mechanism to shorten their life cycle when facing water-deficit conditions. While drought tolerance has been intensively investigated, the genetic and molecular mechanisms of DE remain elusive. We found that low water-deficit treatment (LWT) at the early stage of rice development can trigger early flowering and reduced tiller numbers. LWT induced the accumulation of ABA which in turn feedback affected the light perception and circadian clock by synchronously regulating many flowering-related genes to promote early flowering. Moreover, some of the light receptors, circadian components, and flowering-related genes including OsTOC1, Ghd7, and PhyB were found to be involved in LWT in an ABA-dependent manner, whereas some of the other flowering-related genes including OsGI, OsELF3, OsPRR37, and OsMADS50 were involved in the regulation of DE independent of ABA. In addition, we found that strigolactones and OsTB1 are involved in the tillering inhibition under LWT, which is independent of the flowering pathway in rice. Taken together, our findings provide compelling evidence that DE in rice is coordinately regulated by multiple pathways in the reproduction (flowering) switch.

Schematic model of regulatory interactions 869 in the DE pathway in rice