籽粒白垩是一种不良性状,对水稻的籽粒产量和品质有负面影响。然而,白垩的调节机制很复杂,目前尚不清楚.我们确定了白腹率(WBR)的正调节剂。WBR7基因编码蔗糖合酶3(SUS3)。WBR7的弱功能等位基因有利于提高籽粒产量和品质。在水稻驯化的过程中,WBR7编码区的功能性G/A变异导致GT-4糖基转移酶结构域中的E541K氨基酸取代,与WBR7G(品种Beilu130中的等位基因)相比,导致WBR7A(品种Jin23B中的等位基因)的分解活性显着降低。NIL(J23B)和敲除线NIL(BL130)KO表现出低于NIL(BL130)和NIL(J23B)COM的WBR7分解活性,导致较少的蔗糖在传导器官中的分解和代谢。这导致更多的蔗糖运输到胚乳,增强胚乳中储存成分的合成并导致WBR降低。更多的蔗糖也被输送到花药,为花粉成熟和发芽提供足够的基质和能量供应,最终导致结实率增加和谷物产量增加。我们的发现阐明了通过调节蔗糖代谢和分配来提高水稻产量和品质的机制。并为改善稻米品质提供了有价值的等位基因。
Grain chalkiness is an undesirable trait that negatively regulates grain yield and quality in rice. However, the regulatory mechanism underlying chalkiness is complex and remains unclear. We identified a positive regulator of white-belly rate (WBR). The WBR7 gene encodes sucrose synthase 3 (SUS3). A weak functional allele of WBR7 is beneficial in increasing grain yield and quality. During the domestication of indica rice, a functional G/A variation in the coding region of WBR7 resulted in an E541K amino acid substitution in the GT-4 glycosyltransferase domain, leading to a significant decrease in decomposition activity of WBR7A (allele in cultivar Jin23B) compared with WBR7G (allele in cultivar Beilu130). The NIL(J23B) and knockout line NIL(BL130)KO exhibited lower WBR7 decomposition activity than that of NIL(BL130) and NIL(J23B)COM, resulting in less sucrose decomposition and metabolism in the conducting organs. This caused more sucrose transportation to the endosperm, enhancing the synthesis of storage components in the endosperm and leading to decreased WBR. More sucrose was also transported to the anthers, providing sufficient substrate and energy supply for pollen maturation and germination, ultimately leading to an increase rate of seed setting and increased grain yield. Our findings elucidate a mechanism for enhancing rice yield and quality by modulating sucrose metabolism and allocation, and provides a valuable allele for improved rice quality.