J Exp Bot：PIN基因的遗传修饰诱导留绿干旱适应表型的因果机制

今天介绍的是澳大利亚科学家在Journal of Experimental Botany上发表的研究论文《Genetic modification of PIN genes induces causal mechanisms of stay-green drought adaptation phenotype》。

留绿的特性被认为是全球谷物中一种关键的干旱适应机制。在季末干旱胁迫下，常绿高粱植株的叶片和茎常表现出衰老延缓，从而导致生长时间延长，倒伏风险降低，粮食产量增加。目前已鉴定出45个与留绿相关的QTL，其中包括两个主要的QTL(STG1和STG2)。然而，功能性调控留绿的基因却知之甚少。在本研究中，作者证明了PIN形成的生长素外输出载体家族诱导驱动高粱留绿表型的一些机制，SbPIN4和SbPIN2分别位于STG1和STG2。作者发现11个高粱PIN基因中有9个与已知的留绿QTL一致。在转基因研究中，作者证明了位于高粱STG1(SbPIN4)、STG2(SbPIN2)和Stg3b(SbPIN1)QTL区域的PIN基因对高粱的冠层发育、根部结构和穗部生长具有多效性调节作用。SbPIN1、SbPIN2和SbPIN4在不同器官中的表达与非留绿对照相比存在差异。冠层和根部结构的改变的带来的结果是产生留绿表型。且作物模拟模型表明，SbPIN2表型在干旱条件下可以提高粮食产量。

The stay-green trait is recognised as a key drought adaptation mechanism in cereals worldwide. Stay-green sorghum plants exhibit delayed senescence of leaves and stems, leading to prolonged growth, a reduced risk of lodging and higher grain yield under end-of-season drought stress. More than 45 quantitative trait loci (QTL) associated with stay-green have been identified, including two major QTL (Stg1 and Stg2). However, none of the contributing genes that regulate functional stay-green are known. Here we show that the PIN FORMED family of auxin efflux carriers induce some of the causal mechanisms driving the stay-green phenotype in sorghum, with SbPIN4 and SbPIN2 located in Stg1 and Stg2, respectively. We found that 9 of 11 sorghum PIN genes aligned with known stay-green QTL. In transgenic studies, we demonstrated that PIN genes located within the Stg1 (SbPIN4), Stg2 (SbPIN2) and Stg3b (SbPIN1) QTL regions acted pleiotropically to modulate canopy development, root architecture and panicle growth in sorghum, with SbPIN1, SbPIN2 and SbPIN4 differentially expressed in various organs relative to the non stay-green control. The emergent consequence of such modifications in canopy and root architecture is a stay-green phenotype. Crop simulation modelling shows that the SbPIN2 phenotype can increase grain yield under drought.

原文链接：https://doi.org/10.1093/jxb/erac336

转自：植物科学SCI

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