A NAC-EXPANSIN module enhances maize kernel size by controlling nucellus elimination.
A NAC-EXPANSIN module enhances maize kernel size by controlling nucellus elimination.
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DOI：
10.1038/s41467-022-33513-4
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发表时间：
2022-09-29
影响因子：
16.6
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玉米早期胚乳发育是伴随着母体珠心组织的消失而开始的。然而，潜在的机制在很大程度上是未知的。在这里，我们描述了一个编码EXPANSIN基因ZmEXPB15的玉米籽粒大小和重量的主要数量性状基因座。编码的β-Expansin蛋白在珠心细胞中特异表达，并通过促进珠心细胞的消除来积极控制籽粒大小和重量。我们进一步证明了两个珠心细胞丰富的转录因子(TF)，ZmNAC11和ZmNAC29，激活了ZmEXPB15的表达。相应地，这两个TF还通过珠心消除调节促进籽粒大小和重量，遗传分析支持它们与ZmEXPB15的互作。重要的是，从ZmEXPB15高表达系获得的杂交种增加了粒重，显示了其潜在的育种价值。总之，我们揭示了一条调节母体珠心消除和早期胚乳发育的细胞过程的途径，以及一种提高籽粒重量的方法。目前对玉米籽粒发育的研究主要集中在胚乳和胚胎发育上，对珠心组织的调控知之甚少。在这里，作者报道了一个NAC-EXPB15途径，它通过调节珠心消除和早期胚乳发育来调节玉米籽粒大小。
Maize early endosperm development is initiated in coordination with elimination of maternal nucellar tissues. However, the underlying mechanisms are largely unknown. Here, we characterize a major quantitative trait locus for maize kernel size and weight that encodes an EXPANSIN gene, ZmEXPB15. The encoded β-expansin protein is expressed specifically in nucellus, and positively controls kernel size and weight by promoting nucellus elimination. We further show that two nucellus-enriched transcription factors (TFs), ZmNAC11 and ZmNAC29, activate ZmEXPB15 expression. Accordingly, these two TFs also promote kernel size and weight through nucellus elimination regulation, and genetic analyses support their interaction with ZmEXPB15. Importantly, hybrids derived from a ZmEXPB15 overexpression line have increased kernel weight, demonstrates its potential value in breeding. Together, we reveal a pathway modulating the cellular processes of maternal nucellus elimination and early endosperm development, and an approach to improve kernel weight. Current studies of maize kernel development mostly focus on endosperm and embryo development, and little is known about the control of the nucellus tissue. Here, the authors report a NAC-EXPB15 pathway that regulate maize kernel size by modulating nucellus elimination and early endosperm development.