The Arabidopsis bHLH010/089/091 (basic helix-loop-helix) genes are functionally redundant and are required for both anther development and normal expression of DYT1-activated anther-related genes. These three genes are conserved in Brassicaceae, suggesting that each of them is under selection pressure; however, little is known about the possible functional differences among these bHLH genes and between the bHLH and DYT1 genes. Here, we compared novel anther transcriptomic data sets from bHLH010/089/091 single and double mutants, with an anther transcriptomic data set from the wild type (WT) and a previously obtained anther transcriptomic data set from the bhlh010 bhlh089 bhlh091 triple mutant. The results revealed molecular phenotypes that support the functional redundancy and divergence of bHLH010, bHLH089, and bHLH091, as well as the functional overlap and difference between them and DYT1. DNA-binding analyses revealed that DYT1 and bHLH089 specifically recognize the TCATGTGC box to activate the expression of target genes, including ATA20, EXL4, and MEE48. In addition, among genes whose expression was affected in the bhlh010 bhlh089 double and bhlh010 bhlh089 bhlh091 triple mutants, genes that are involved in the stress response and cell signaling were enriched, which included 256 genes whose expression was preferentially induced by heat during early flower development. Moreover, the bhlh double mutants exhibited defective pollen development when the plants were grown under elevated temperature, suggesting that bHLH genes are important for anther gene expression under such conditions. These results are consistent with the observation that the heat-induced expression of several genes is less in the bhlh mutants than that in the WT. Therefore, our results provide important insights into the molecular mechanism underlying the activation of direct targets by DYT1-bHLH089 heterodimers and demonstrate the protective roles of bHLH010/089/091 in maintaining fertility upon heat stress.

的拟南芥bHLH010 / 089/091（碱性螺旋-环-螺旋）的基因是功能冗余的和所需要的的DYT1活化花药相关基因二者花药发育和正常表达。这三个基因在十字花科中是保守的，表明它们每个都处于选择压力下。但是，对于这些bHLH基因之间以及bHLH和DYT1基因之间可能的功能差异知之甚少。在这里，我们比较了来自bHLH010 / 089/091单突变体和双重突变体的新型花药转录组数据集，与野生型（WT）的花药转录组数据集和先​​前从野生型（WT）获得的花药转录组数据集。bhlh010 bhlh089 bhlh091三重突变体。结果显示分子表型支持bHLH010，bHLH089和bHLH091的功能冗余和差异，以及它们与DYT1之间的功能重叠和差异。DNA结合分析显示DYT1和bHLH089特异性识别TCATGTGC框，以激活包括ATA20，EXL4和MEE48在内的靶基因的表达。另外，在表达受bhlh010 bhlh089 double和bhlh010 bhlh089 bhlh091影响的基因中在三重突变体中，涉及胁迫反应和细胞信号转导的基因得到了丰富，其中包括256个基因，其表达在花朵早期发育过程中受热优先诱导。而且，当植物在高温下生长时，bhlh双突变体表现出有缺陷的花粉发育，表明bHLH基因对于在这种条件下的花药基因表达很重要。这些结果与以下观察结果一致，即bhlh中几种基因的热诱导表达较少突变体比野生型。因此，我们的结果为DYT1-bHLH089异二聚体激活直接靶标的分子机制提供了重要的见识，并证明了bHLH010 / 089/091在维持热应激下的生育能力中的保护作用。