ABA‐triggered ROS burst in rice developing anthers is critical for tapetal programmed cell death induction and heat stress‐induced pollen abortion

Abstract

High temperatures (HT) cause pollen abortion and poor floret fertility in rice, which is closely associated with excessive accumulation of reactive oxygen species (ROS) in the developing anthers. However, the relationships between accumulation of abscisic acid (ABA) and ROS, and their effects on tapetum-specific programmed cell death (PCD) in HT-stressed anthers are poorly characterised. Here, we determined the spatiotemporal changes in ABA and ROS levels, and their relationships with tapetal PCD under HT exposure. Mutants lacking ABA-activated protein kinase 2 (SAPK2) functions and exogenous ABA treatments were used to explore the effects of ABA signalling on the induction of PCD and ROS accumulation during pollen development. HT-induced pollen abortion was tightly associated with ABA accumulation and oxidative stress. The higher ABA level in HT-stressed anthers resulted in the earlier initiation of PCD induction and subsequently abnormal tapetum degeneration by activating ROS accumulation in developing anthers.Interactions between SAPK2 and DEAD-box ATP-dependent RNA helicase elF4A-1 (RH4) were required for ABA-induced ROS generation in developing anthers. The OsSAPK2 knockout mutants showed the impaired PCD responses in the absence of HT. However, the deficiency of SAPK2 functions did not suppress the ABAmediated ROS generation in HT-stressed anthers.

ROS accumulation-induced tapetal PCD timing changes leads to microspore abortion in cotton CMS lines

“…Actually, during the process of normal anthers development, the amount of ROS usually increased at the particular stage of the tapetum abortion process, and the peak time of ROS production was associated with stage-specific expression of NADPH oxidase, especially RBOHE [ 50 , 56 , 57 ]. Recent study had identified that abscisic acid (ABA) could trigger ROS burst in rice developing anthers leading to tapetal PCD when experiencing heat stress [ 69 ]. This excess ROS production in stress-induced male sterility also related to NADPH oxidase on account of ABA stimulated the hyperpolarization-activated Ca 2+ channels and up-regulated the activity of NADPH oxidase [ 70 ].…”

The 14-3-3 Protein BdGF14a Increases the Transcriptional Regulation Activity of BdbZIP62 to Confer Drought and Salt Resistance in Tobacco

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