Study On The Role Of SlALKBH3 In Tomato Flower Stalk Abscission

Tomato is one of the most important vegetable crops because of its diverse,nutritious and extensive cultivation.However,during the production of tomato in facilities,flower and fruit drop due to low temperature and low light seriously affects the yield of tomato and is one of the important factors leading to yield decline in tomato facilities,among which,the effect of plant hormones on tomato petiole abscission is very important.However,in the research exploration of tomato petiole abscission,reports on epigenetic effects on tomato petiole abscission are at an unknown stage,and epigenetic modifications mainly include three types of modifications:DNA modifications,RNA modifications,and protein modifications.In recent years,with the rapid development of DNA modification and protein modification,RNA methylation modification research has also emerged.m~6A(N6-methyladenosine)is one of the most common RNA modifications on m RNA,which is widely present and distributed in eukaryotes.However,the exploration of m~6A methylation in tomato has only just begun,and the specific molecular function in tomato petiole abscission in particular has remained unknown.In this experiment,we screened the demethylase SLALKBH3,which has an effect on abscission,and analyzed its transcriptome sequencing,and resolved its mechanism of action in regulating abscission.The main findings are as follows:1.Tomato flower stalks were treated with demethylated overexpressed transgenic plants FTO and demethylation inhibitors,respectively,and the abscission rate was measured.The results showed that demethylation affected tomato flower stalks abscission.2.Screening of demethylated genes:Quantitative analysis of Sl ALKBHs family genes in isolated region of tomato flower stem showed that the expression levels of Sl ALKBH1,Sl ALKBH2,Sl ALKBH3,Sl ALKBH4,Sl ALKBH5 and Sl ALKBH8 were relatively high.Then Sl ALKBH1,Sl ALKBH2,Sl ALKBH3,Sl ALKBH4,Sl ALKBH5 and Sl ALKBH8 were quantitatively analyzed at key time points of 0 h,2 h,4 h,8 h and 16 h after shedding.The results showed that the expression levels of Sl ALKBH2 and Sl ALKBH8 decreased during shedding.The expression of Sl ALKBH3 and Sl ALKBH5 increased during abscission.3.Sl ALKBH2,Sl ALKBH8,Sl ALKBH3 and Sl ALKBH5 were treated with VIGS.The results showed that Sl ALKBH3 played a significant role in the abscission process.Silencing Sl ALKBH3 significantly accelerated the abscission of tomato flower stalks.4.The isolated regions of p TRV-Empty and VIGS silent plants Sl ALKBH3(p TRV-Sl ALKBH3)at the critical stage of shedding(8h after flowering)were taken for Me RIP-Seq sequencing analysis.The sequencing results showed that the peak value of m~6A modification in CDS region and 3’UTR region changed significantly.5.In the analysis of sequencing results,the plant hormone genes in the CDS region and the 3’UTR region were analyzed,and after screening,they were found to mainly affect the expression of ethylene genes.In the p TRV-SLALKBH3 plant,quantitative analysis showed that the expression level of ETR4 in the 3’UTR region was decreased compared with that of the control.This indicated that SLALKBH3 could regulate tomato stalk shedding by affecting the expression of m~6A modification of ethylene-related gene in the 3’UTR region.