Table_2_Natural variation and domestication selection of ZmSULTR3;4 is associated with maize lateral root length in response to salt stress.xlsx

Soil salinity is a major constraint that restricts crop productivity worldwide. Lateral roots (LRs) are important for water and nutrient acquisition, therefore understanding the genetic basis of natural variation in lateral root length (LRL) is of great agronomic relevance to improve salt tolerance in cultivated germplasms. Here, using a genome-wide association study, we showed that the genetic variation in ZmSULTR3;4, which encodes a plasma membrane-localized sulfate transporter, is associated with natural variation in maize LRL under salt stress. The transcript of ZmSULTR3;4 was found preferentially in the epidermal and vascular tissues of root and increased by salt stress, supporting its essential role in the LR formation under salt stress. Further candidate gene association analysis showed that DNA polymorphisms in the promoter region differentiate the expression of ZmSULTR3;4 among maize inbred lines that may contribute to the natural variation of LRL under salt stress. Nucleotide diversity and neutrality tests revealed that ZmSULTR3;4 has undergone selection during maize domestication and improvement. Overall, our results revealed a regulatory role of ZmSULTR3;4 in salt regulated LR growth and uncovered favorable alleles of ZmSULTR3;4, providing an important selection target for breeding salt-tolerant maize cultivar.

土壤盐渍化是全球范围内限制作物产量的重要制约因素。侧根（LRs）对于水分和营养的获取至关重要，因此，理解侧根长度（LRL）自然变异的遗传基础，对于提高栽培种质资源的耐盐性具有重要的农学意义。在本研究中，通过全基因组关联分析，我们揭示了编码质膜定位的硫酸盐转运蛋白的ZmSULTR3;4基因中的遗传变异与盐胁迫下玉米侧根长度的自然变异相关。ZmSULTR3;4的转录本主要存在于根的表皮和维管组织中，且在盐胁迫下表达量增加，这证实了其在盐胁迫下侧根形成中的关键作用。进一步的候选基因关联分析表明，启动子区域的DNA多态性区分了玉米自交系中ZmSULTR3;4的表达，这可能是导致盐胁迫下LRL自然变异的原因。核苷酸多样性和中性检验结果表明，ZmSULTR3;4在玉米驯化和改良过程中经历了选择。总体而言，我们的研究结果揭示了ZmSULTR3;4在盐调节的侧根生长中的调控作用，并发现了ZmSULTR3;4的有利等位基因，为培育耐盐玉米品种提供了重要的育种选择目标。