Regulations of m6A methylation on tomato fruit chilling injury

Tomato fruit are sensitive to chilling injury (CI) during cold storage. Several factors have been discovered to be involved in chilling injury of tomato fruit. Plant hormones play an important regulatory role, however, the relationship between chilling injury and N6-methyladenosine (m6A) methylation of transcripts in plant hormone pathways has not been reported yet. In order to clarify the complex regulatory mechanism of m6A methylation on chilling injury in tomato fruit, Nanopore direct RNA sequencing was employed. A large number of enzymes and transcription factors were found to be involved in the regulation process of fruit chilling injury, which were associated with plant hormone, such as 1-aminocyclopropane 1-carboxylate synthase (ACS), aspartate aminotransferase (AST), auxin response factor (ARF2), ethylene response factor 2 (ERF2), gibberellin 20-oxidase-3 (GA20ox) and jasmonic acid (JA). By conjoint analysis of the differential expression transcripts related to chilling injury and m6A methylation differential expression transcripts 41 differential expression transcripts were identified involved in chilling injury including 1-aminocyclopropane-1-carboxylate oxidase (ACO) and pectinesterase (PE) were down-regulated and heat shock cognate 70 kD protein 2 (cpHSC70), HSP70-binding protein (HspBP) and salicylic acid-binding protein 2 (SABP2) were up-regulated. Our results will provide a deeper understanding for chilling injury regulatory mechanism and post-harvest cold storage of tomato fruit.