Tiller number is a crucial agronomic trait that directly affects the number of effective panicles and yield formation in rice. Here, we report a semi-dwarf and low tillering mutant Osdlt10 (dwarf and low tillering 10) that exhibited reduced tiller number, semi-dwarfism, increased grain width, low seed-setting rate, curled leaf tip and a series of abnormalities of agronomic traits. Phenotypic observations showed that Osdlt10 mutants had defects in tiller bud formation and grew slowly at the tillering stage. Map-based cloning revealed that LOC_Os10g41310 was the responsible gene for OsDLT10, which was subsequently demonstrated using the CRISPR/Cas9 system and a complementary experiment. Expression pattern analysis indicated that OsDLT10 was primarily expressed in the stem node, the basic part of axillary bud and leaf sheath, pulvinus. The hormone treatment investigation indicated that extremely high of exogenous auxin concentrations can inhibit the expression of OsDLT10. Endogenous auxin content decreased significantly at the base of stem node and axillary bud in Osdlt10 mutants. The results showed that OsDLT10 was related to auxin. qPCR analysis results further showed that the expression levels of auxin transport genes (PINs) and early response genes (IAAs) were significantly increased. The expression levels of WUS-like and FON1 were substantially decreased in the Osdlt10 mutants. These results revealed that OsDLT10 played a critical role in influencing tiller number, likely in association with hormone signals and the WUS-CLV pathway, to regulate axillary bud development in rice.

中文翻译：

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水稻矮化和低分蘖 10 (OsDLT10) 通过监测生长素稳态来调节分蘖数

分蘖数是直接影响水稻有效穗数和产量形成的重要农艺性状。在这里，我们报告了一个半矮化和低分蘖突变体 Osdlt10（矮化和低分蘖 10），其表现出分蘖数减少、半矮化、粒宽增加、结实率低、叶尖卷曲和一系列农艺异常。性状。表型观察表明，Osdlt10 突变体在分蘖芽形成方面存在缺陷，并且在分蘖阶段生长缓慢。基于图谱的克隆显示 LOC_Os10g41310 是 OsDLT10 的负责基因，随后使用 CRISPR/Cas9 系统和补充实验证明了这一点。表达模式分析表明，OsDLT10主要在茎节、腋芽和叶鞘的基部、叶柄中表达。激素处理研究表明，极高的外源生长素浓度可抑制 OsDLT10 的表达。Osdlt10突变体茎节基部和腋芽的内源生长素含量显着降低。结果表明OsDLT10与生长素有关。qPCR分析结果进一步表明，生长素转运基因（PINs）和早期反应基因（IAAs）的表达水平显着增加。WUS-like 和 FON1 的表达水平在 Osdlt10 突变体中显着降低。这些结果表明，OsDLT10 在影响分蘖数方面发挥了关键作用，可能与激素信号和 WUS-CLV 通路有关，以调节水稻腋芽发育。