Data_Sheet_1_Characteristics of members of IGT family genes in controlling rice root system architecture and tiller development.docx

Root system architecture (RSA) and tiller are important agronomic traits. However, the mechanisms of the IGT family genes regulate RSA and tiller development in different rice varieties remain unclear. In this study, we demonstrated that 38 rice varieties obtained from Yuanyang Hani’s terraced fields with different RSA and could be classified into six groups based on the ratio of root length and width. We found a positive correlation between RSA (including root width, length, and area) and tiller number in most of rice varieties. Furthermore, the IGT family genes Deeper Rooting 1 (DRO1), LAZY1, TAC1, and qSOR1 showed different expression patterns when rice grown under irrigation and drought conditions. Moreover, the qSOR1 gene had higher levels in the roots and tillers, and accompanied with higher levels of PIN1b gene in roots when rice grown under drought environmental condition. DRO1 gene had two single nucleotide polymorphisms (SNPs) in the exon 3 sequences and showed different expression patterns in the roots and tillers of the 38 rice varieties. Overexpression of DRO1 with a deletion of exon 5 caused shorter root length, less lateral roots and lower levels of LAZY1, TAC1, and qSOR1. Further protein interaction network, microRNA targeting and co-expression analysis showed that DRO1 plays a critical role in the root and tiller development associated with auxin transport. These data suggest that the RSA and tiller development are regulated by the IGT family genes in an intricate network way, which is tightly related to rice genetic background in rice adapting to different environmental conditions.

根系构型（RSA）和分蘖是重要的农艺性状。然而，IGT家族基因调控不同水稻品种RSA及分蘖发育的机制尚不明确。在本研究中，我们展示了从元阳哈尼梯田采集的38个具有不同RSA的水稻品种，可根据根长与宽的比例分为六组。我们发现，在大多数水稻品种中，RSA（包括根宽、长和面积）与分蘖数量呈正相关。此外，IGT家族基因中的Deeper Rooting 1（DRO1）、LAZY1、TAC1和qSOR1在水稻灌溉和干旱条件下的表达模式存在差异。进一步研究发现，qSOR1基因在根系和分蘖中的含量较高，在干旱环境下，其与PIN1b基因在根系中的含量亦较高。DRO1基因在第3外显子序列中存在两个单核苷酸多态性（SNPs），在不同水稻品种的根系和分蘖中表现出不同的表达模式。DRO1基因外显子5的缺失导致其过表达，从而引起根系长度缩短、侧根减少以及LAZY1、TAC1和qSOR1水平降低。进一步的蛋白质互作网络、microRNA靶向及共表达分析表明，DRO1在根系和分蘖发育中与生长素运输相关的过程中发挥关键作用。这些数据表明，RSA和分蘖发育受IGT家族基因在复杂网络中的调控，这与水稻适应不同环境条件下的遗传背景密切相关。