Salicylic acid reverses pollen abortion of rice caused by heat stress

Abstract

BackgroundExtremely high temperatures are becoming an increasingly severe threat to crop yields. It is well documented that salicylic acid (SA) can enhance the stress tolerance of plants; however, its effect on the reproductive organs of rice plants has not been described before. To investigate the mechanism underlying the SA-mediated alleviation of the heat stress damage to rice pollen viability, a susceptible cultivar (Changyou1) was treated with SA at the pollen mother cell (PMC) meiosis stage and then subjected to heat stress of 40 °C for 10 d until 1d before flowering.ResultsUnder control conditions, no significant difference was found in pollen viability and seed-setting rate in SA treatments. However, under heat stress conditions, SA decreased the accumulation of reactive oxygen species (ROS) in anthers to prevent tapetum programmed cell death (PCD) and degradation. The genes related to tapetum development, such as EAT1 (Eternal Tapetum 1), MIL2 (Microsporeless 2), and DTM1 (Defective Tapetum and Meiocytese 1), were found to be involved in this process. When rice plants were exogenously sprayed with SA or paclobutrazol (PAC, a SA inhibitor) + H2O2 under heat stress, a significantly higher pollen viability was found compared to plants sprayed with H2O, PAC, or SA + dimethylthiourea (DMTU, an H2O2 and OH· scavenger). Additionally, a sharp increase in H2O2 was observed in the SA or PAC+ H2O2 treatment groups compared to other treatments.ConclusionWe suggest that H2O2 may play an important role in mediating SA to prevent pollen abortion caused by heat stress through inhibiting the tapetum PCD.Electronic supplementary materialThe online version of this article (10.1186/s12870-018-1472-5) contains supplementary material, which is available to authorized users.

Heat stress during flowering in cereals – effects and adaptation strategies

“…Although, ROS scavenging is key to ensure that heat stress does not damage the sensitive reproductive tissue, ROS‐dependent programmed cell death is essential for successful fertilisation (Suzuki & Katano, ). Some thermo‐protectants including primary metabolites and phyto‐hormones such as ‐aminobutyric acid (mungbean ( Vigna radiate ), Priya et al , ); salicylic acid (rice, Feng et al , ); flavonols (tomato, Muhlemann et al , ); auxin (rice, Zhang et al , ); and ethylene (tomato, Jegadeesan et al , ) continue to be effective in alleviating heat stress damage in pollen. Although, there are no studies in this direction involving pistils per se , a plausible hypothesis would be that the above‐mentioned compounds will have a similar alleviation potential in pistils exposed to heat stress (Box 2).…”

Acid invertase confers heat tolerance in rice plants by maintaining energy homoeostasis of spikelets

“…Heat stress is one of the most important abiotic stresses and causes irreversible damage to rice plants (Jajoo & Allakhverdiev, ; Kumazaki & Suzuki, ), resulting in the inactivation of thermolabile proteins, ROS accumulation, and ultimately PCD (Feng et al, ; Singh et al, ). If such stress occurs at the reproductive stage, grain yield is significantly decreased (Feng et al, ; Fu et al, ; Zhang et al, ). At anthesis, the pollen germination and pollen tube elongation are inhibited by heat stress, which was mainly inferred due to an energy imbalance (Zhang et al, ).…”

Peer Review #2 of "Comparative transcriptome analysis of panicle development under heat stress in two rice (Oryza sativa L.) cultivars differing in heat tolerance (v0.1)"

“…WRKY genes encode TFs that play important roles in abiotic stress responses , especially to abscisic acid (ABA) (Zhen et al 2005). In this study, six DEGs were WRKY TFs, namely, BGIOSGA003134, BGIOSGA017063, BGIOSGA029574, BGIOSGA005924, BGIOSGA024948, and BGIOSGA033505, which might promote young panicle development associated with sucrose consumption mediated by ABA under high temperature (Feng et al 2018). However, few studies have reported the relationship between the WRKY family and heat resistance, which should be further studied.…”