Soil salinity affects the expression of serine/arginine-rich (SR) genes and isoforms by alternative splicing, which in turn regulates the adaptation of plants to stress.  We previously identified the cassava spliceosomal component 35 like (SCL) and SR subfamilies, belonging to the SR protein family, which are extensively involved in responses to abiotic stresses.  However, the post-transcriptional regulatory mechanism of cassava arginine/serine-rich (RS) subfamily in response to salt stress remains to be explored.  In the current study, we identified 37 genes of the RS subfamily from 11 plant species and systematically investigated the transcript levels of the RS40 and RS31 genes under diverse abiotic stress conditions.  Subsequently, an analysis of the conserved protein domains revealed that plant RS subfamily genes were likely to preserve their conserved molecular functions and played critical functional roles in responses to abiotic stresses.  Importantly, we found that overexpression of MeRS40 in Arabidopsis enhanced salt tolerance by maintaining reactive oxygen species homeostasis and up-regulating the salt-responsive genes.  However, overexpression of MeRS40 gene in cassava reduced salt tolerance due to the depression of its endogenous gene expression by negative autoregulation of its own pre-mRNA.  Moreover, the MeRS40 protein interacted with MeU1-70Ks (MeU1-70Ka and MeU1-70Kb) in vivo and in vitro, respectively.  Therefore, our findings highlight the critical role of cassava SR proteins in responses to salt stress in plants. 

The frequent occurrence of hailstorm in Xinjiang affects cotton (Gossypium hirsutum L.) production and causes enormous economic loss.  The indeterminate growth habit of cotton allows for varying degrees of recovery and yield when different hail damage levels occur at different stages, which brings inconvenience to agricultural insurance claims and post-damage management.  Therefore, this study aimed to elucidate cotton recovery and yield responses to different levels of simulated hail damage at different growth stages.  Four levels of hail damage (0, 30, 60, and 90%) were simulated every 15 d from the five-leaf stage to the boll opening stage in 2018 and 2019, for a total of six times (I, II, III, IV, V, and VI).  The results showed that seed cotton yield decreased as the damage level increased and yield reduction increased when the damage was applied to older plants (for 30, 60 and 90% damage levels, yield reduction was 9–17%, 22–37% and 48–71%, respectively).  One possible reason was that the leaf area index and leaf area duration of plant canopy decreased after hail damage, resulting in a reduction in the accumulation of above-ground biomass.  However, when hail damage occurred before bloom, due to the indeterminate growth habit of cotton, the vegetative organs produced a strong compensation ability that promoted the bud development.  The compensation ability of vegetative organs decreased when hail damage occurred after bloom and the recovery time was too short to promote new boll maturity.  As the first study to understand the recovery of cotton after hail damage, it analyzed the leaf area index, leaf area duration, above-ground biomass accumulation and yield, rather than the yield alone.  The findings are of great importance for cotton production as they inform decisions about post-damage management practices, yield forecasts and insurance compensation.