RNA N6-Methyladenosine Responds to Low-Temperature Stress in Tomato Anthers

Cold stress is a serious threat to subtropical crop pollen development and induces yield decline. N6-methyladenosine (m(6)A) is the most frequent mRNA modification and plays multiple physiological functions in plant development. However, whether m(6)A regulates pollen development is unclear, and its putative role in cold stress response remains unknown. Here, we observed that moderate low-temperature (MLT) stress induced pollen abortion in tomato. This phenotype was caused by disruption of tapetum development and pollen exine formation, accompanied by reduced m(6)A levels in tomato anther. Analysis of m(6)A-seq data revealed 1,805 transcripts displayed reduced m(6)A levels and 978 transcripts showed elevated m(6)A levels in MLT-stressed anthers compared with those in anthers under normal temperature. These differentially m(6)A enriched transcripts under MLT stress were mainly related to lipid metabolism, adenosine triphosphatase (ATPase) activity, and ATP-binding pathways. An ATP-binding transcript, SlABCG31, had significantly upregulated m(6)A modification levels, which was inversely correlated to the dramatically downregulated expression level. These changes correlated with higher abscisic acid (ABA) levels in anthers and disrupted pollen wall formation under low-temperature stress. Our findings characterized m(6)A as a novel layer of complexity in gene expression regulation and established a molecular link between m(6)A methylation and tomato anther development under low-temperature conditions.

Automated summary

Moderate low-temperature stress induced pollen abortion in tomato by disrupting tapetum development and pollen exine formation. Changes in m(6)A levels were associated with altered expression of transcripts related to lipid metabolism, ATPase activity, and ATP-binding pathways under low-temperature stress. m(6)A modification was inversely correlated with the expression level of an ATP-binding transcript, which affected pollen wall formation and abscisic acid (ABA) levels in anthers.