Auxin apical dominance governed by the OsAsp1-OsTIF1 complex determines distinctive rice caryopses development on different branches.
Auxin apical dominance governed by the OsAsp1-OsTIF1 complex determines distinctive rice caryopses development on different branches.
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由OsAsp1-OsTIF1复合体控制的生长素顶端优势决定了水稻颖果在不同分枝上的发育差异。
DOI：
10.1371/journal.pgen.1009157
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发表时间：
2020-10
期刊：
影响因子：
4.5
通讯作者：
Wang Y
中科院分区：
文献类型：
--
作者：
Chang S;Chen Y;Jia S;Li Y;Liu K;Lin Z;Wang H;Chu Z;Liu J;Xi C;Zhao H;Han S;Wang Y
水稻（Oryza sativa）中，位于近端二次枝梗（CSB）上的颖果比位于顶端一次枝梗（CPB）上的颖果具有更小的籽粒大小和更差的籽粒灌浆，这极大地限制了籽粒产量。然而，负责CPB和CSB之间的发育差异的分子机制仍然难以捉摸。在这个全转录组的表达研究中，我们确定了基因天冬氨酸蛋白酶1（OsAsp 1），它达到一个更早和更高的转录高峰在CPB比CSB授粉后。在杂合T-DNA系asp 1 -1+/-中OsAsp 1表达的破坏消除了CPB和CSB之间的发育差异。OsAsp 1负调控生长素生物合成的转录抑制因子OsTAA 1转录抑制因子1（OsTIF 1），以维持CPB和CSB中吲哚乙酸（IAA）的顶端优势。IAA还通过释放OsTIF 1与OsAsp 1的相互作用促进OsTIF 1从内质网（ER）向细胞核的转移，并通过反馈环调节颖果中IAA的水平。IAA通过MADS 29促进OsAsp 1的转录，以维持授粉过程中CPB和CSB之间的OsAsp 1差异。总之，这些研究结果提供了一个机制解释的生长素分布之间的差异CPBs和CSB调节不同的颖果发育在不同的水稻分支和潜在的目标工程作物产量提高。水稻是我国重要的粮食作物和重要的模式植物。与水稻顶生一次枝梗上的颖果相比，近生二次枝梗上的颖果籽粒较小，灌浆较差，严重限制了水稻产量潜力的发挥，特别是在超级稻品种中。在这项研究中，我们证明，高吲哚-3-乙酸（IAA）水平上调天冬氨酸蛋白酶1（OsAsp 1）转录通过MADS 29授粉后产生更高的OsAsp 1水平在CPB中比在CSB。OsAsp 1与内质网中的OsTAA 1转录抑制因子1（OsTIF 1）相互作用，解除OsTIF 1对OsTAA 1的转录抑制作用，使受精后第5天CPB中IAA含量达到峰值。IAA通过降低OsTIF 1与OsAsp 1的相互作用，促进OsTIF 1从内质网向细胞核的转移，反馈调节颖果中IAA的水平。因此，在CPB和CSB之间的差异生长素水平由OsAsp 1-OsTIF 1复合物决定，并且对于CPB和CSB的不同发育是必不可少的，为作物的工程产量改良提供了潜在的靶标。
In rice (Oryza sativa), caryopses located on proximal secondary branches (CSBs) have smaller grain size and poorer grain filling than those located on apical primary branches (CPBs), greatly limiting grain yield. However, the molecular mechanism responsible for developmental differences between CPBs and CSBs remains elusive. In this transcriptome-wide expression study, we identified the gene Aspartic Protease 1 (OsAsp1), which reaches an earlier and higher transcriptional peak in CPBs than in CSBs after pollination. Disruption of OsAsp1 expression in the heterozygous T-DNA line asp1-1+/–eliminated developmental differences between CPBs and CSBs. OsAsp1 negatively regulated the transcriptional inhibitor of auxin biosynthesis, OsTAA1 transcriptional inhibition factor 1 (OsTIF1), to preserve indole-3-acetic acid (IAA) apical dominance in CPBs and CSBs. IAA also facilitated OsTIF1 translocation from the endoplasmic reticulum (ER) to the nucleus by releasing the interaction of OsTIF1 with OsAsp1 to regulate caryopses IAA levels via a feedback loop. IAA promoted transcription of OsAsp1 through MADS29 to maintain an OsAsp1 differential between CPBs and CSBs during pollination. Together, these findings provide a mechanistic explanation for the distributed auxin differential between CPBs and CSBs to regulate distinct caryopses development in different rice branches and potential targets for engineering yield improvement in crops. Rice is a major food crop and an important model plant. Compared with caryopses on apical primary branches (CPBs) of rice, those located on proximal secondary branches (CSBs) display smaller grains and poor grain filling, which greatly limit rice yield potential fulfilment, especially among ‘super’ rice cultivars. In this study, we demonstrated that high indole-3-acetic (IAA) levels upregulated Aspartic Protease 1 (OsAsp1) transcription via MADS29 post-pollination to produce higher OsAsp1 levels in CPBs than in CSBs. OsAsp1 then interacted with OsTAA1 transcriptional inhibition factor 1 (OsTIF1) in the endoplasmic reticulum (ER) to dispel OsTIF1 transcriptional inhibition of OsTAA1, causing IAA content to peak in CPBs at 5 days after fertilisation (DAF). IAA facilitated OsTIF1 translocation from the ER to the nucleus by reducing its interaction with OsAsp1 as feedback regulation of IAA levels in caryopses. Thus, differential auxin levels between CPBs and CSBs are determined by the OsAsp1-OsTIF1 complex, and are essential for the distinct development of CPBs and CSBs, providing potential targets for engineering yield improvement in crops.
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影响因子：
5.1
作者：
Bart R;Chern M;Park CJ;Bartley L;Ronald PC
通讯作者：
Ronald PC
GS5 的自然变异在调节水稻籽粒大小和产量方面发挥着重要作用
影响因子：
30.8
作者：
Li, Yibo;Fan, Chuchuan;Zhang, Qifa
通讯作者：
Zhang, Qifa
DOI：
10.1073/pnas.1316278111
发表时间：
2014-02-11
影响因子：
11.1
作者：
Franco-Zorrilla, Jose M.;Lopez-Vidriero, Irene;Solano, Roberto
通讯作者：
Solano, Roberto
影响因子：
14.9
作者：
Ouyang S;Zhu W;Hamilton J;Lin H;Campbell M;Childs K;Thibaud-Nissen F;Malek RL;Lee Y;Zheng L;Orvis J;Haas B;Wortman J;Buell CR
通讯作者：
Buell CR
影响因子：
7.2
作者：
Bowler, C;Benvenuto, G;Paszkowski, J
通讯作者：
Paszkowski, J