Escola Superior de Agricultura "Luiz de Queiroz", University of São Paulo, 13418-900 São Paulo, Brazil.
Laboratoire de Recherche en Sciences Végétales, Université de Toulouse, CNRS, UPS, 24 chemin de Borde Rouge, 31320 Auzeville-Tolosane, France.
Int J Mol Sci. 2020 Sep 29;21(19):7191. doi: 10.3390/ijms21197191.
Exogenous low pH stress causes cell death in root cells, limiting root development, and agricultural production. Different lines of evidence suggested a relationship with cell wall (CW) remodeling players. We investigated whether class III peroxidase (CIII Prx) total activity, CIII Prx candidate gene expression, and reactive oxygen species (ROS) could modify CW structure during low pH-induced cell death in roots. Wild-type roots displayed a good spatio-temporal correlation between the low pH-induced cell death and total CIII Prx activity in the early elongation (EZs), transition (TZs), and meristematic (MZs) zones. In situ mRNA hybridization showed that transcripts accumulated only in roots treated at pH 4.6 in the same zones where cell death was induced. Furthermore, roots of the knockout mutant showed decreased cell mortality under low pH compared to wild-type roots. Among the ROS, there was a drastic decrease in O levels in the MZs of wild-type and roots upon low pH stress. Together, our data demonstrate that expression is induced by low pH and that the produced protein could positively regulate cell death. Whether the decrease in O level is related to cell death induced upon low pH treatment remains to be elucidated.
外源性低 pH 胁迫会导致根细胞死亡，从而限制根系发育和农业生产。有不同的证据表明，细胞壁（CW）重塑参与者与之相关。我们研究了在低 pH 诱导的根细胞死亡过程中，过氧化物酶（CIII Prx）总活性、CIII Prx 候选基因表达和活性氧（ROS）是否可以改变 CW 结构。在早期伸长区（EZs）、过渡区（TZs）和分生区（MZs）中，WT 根在低 pH 诱导的细胞死亡和总 CIII Prx 活性之间显示出良好的时空相关性。原位 mRNA 杂交显示，在 pH4.6 处理的根中，只有 转录本在诱导细胞死亡的相同区域积累。此外，与 WT 根相比，突变体的根在低 pH 下的细胞死亡率降低。在 ROS 中，WT 和 根在低 pH 胁迫下 MZs 中的 O 水平急剧下降。总之，我们的数据表明，低 pH 诱导 表达，并且产生的蛋白可能正向调节细胞死亡。O 水平的降低是否与低 pH 处理诱导的细胞死亡有关仍有待阐明。
