The DROOPING LEAF and OsETTIN2 genes promote awn development in rice
The DROOPING LEAF and OsETTIN2 genes promote awn development in rice
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DOI：
10.1111/tpj.12411
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发表时间：
2014-02-01
期刊：
影响因子：
7.2
通讯作者：
Hirano, Hiro-Yuki
中科院分区：
文献类型：
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作者：
Toriba, Taiyo;Hirano, Hiro-Yuki
芒是一个长的针状附属物，在一些禾本科植物中，形成于外稃上，外稃与内稃一起包围花器官。在水稻中，大多数野生种和大多数品系的水稻亚种。印度产生芒，而大多数菌株的O.sativa ssp.日本没有。在日本，长芒的特点似乎已经失去了驯化和育种计划。在此，我们发现DROOPING LEAF（DL）和OsETTIN 2（OsETT2）基因参与有芒籼稻品系Kasalath的芒发育。遗传分析和RNA沉默实验表明DL和OsETT2在芒的形成中独立起作用，并且单独的任何一个基因都不足以促进芒的发育。扫描电子显微镜显示，外稃（一个假定的芒原基）的顶部区域是在一个awnless小花比在一个awnned小花大。OsETT2在有芒的籼稻小花的芒原基中表达，而在无芒的粳稻小花中除原维管束外不表达。DL在籼型和粳型小花中的原基下方以相似的水平表达，表明非细胞自主作用。我们推测OsETT2在芒原基中表达的缺失可能与粳稻株系芒形成的失败有关。
The awn is a long needle-like appendage that, in some grass species, is formed on the lemma that encloses floral organs together with the palea. In rice, most wild species and most strains of Oryza sativa ssp. indica generate an awn, whereas most strains of O.sativa ssp. japonica do not. In japonica, the long-awn characteristic appears to have been lost during domestication and breeding programs. Here, we found that the genes DROOPING LEAF (DL) and OsETTIN2 (OsETT2) are involved in awn development in the awned indica strain Kasalath. Genetic analyses and RNA-silencing experiments indicate that DL and OsETT2 act independently in awn formation, and that either gene alone is not sufficient for awn development. Scanning electron microscopy revealed that the top region of the lemma (a putative awn primordium) is larger in an awned floret than in an awnless floret. OsETT2 is expressed in the awn primordium in the awned indica floret, but not in the awnless japonica floret except in the provascular bundle. DL is expressed underneath the primordium at similar levels in both indica and japonica florets, suggesting non-cell-autonomous action. We hypothesize that loss of expression of OsETT2 in the awn primordium is probably associated with the failure of awn formation in japonica strains.