植物异源嫁接中转移mRNA序列与功能分析

Sequence and functional analysis of mobile mRNAs in the heterologous grafted plants

【目的】本研究拟对异源嫁接植物中的转移mRNA进行分析,探讨序列及功能特征对mRNA转移的影响,揭示m RNA转移的原理,为嫁接的定向调控提供理论依据。【方法】基于已报道的嫁接转录组数据,利用TBtools软件计算转移mRNA的编码区长度、GC含量,通过EXCEL软件分析比较二者与mRNA转移的关系,通过BLASTP同源性分析鉴定各嫁接体中的共转移mRNA,利用GO与KEGG数据库对共转移mRNA进行功能注释及代谢通路分析。【结果】(1)统计分析显示,茎向(由砧木到接穗)和根向(由接穗到砧木)转移mRNA长度的均值分别为1573 bp和1547 bp;随着m RNA长度的增加,mRNA转移率逐渐增加;根向的mRNA转移率显著大于茎向,且随着mRNA长度增大,根向的m RNA转移率增加的趋势更为明显。(2)转移mRNA的平均GC含量介于44%~47%之间;随GC含量增加,mRNA转移率先快速提高,后缓慢降低。GC含量在52%~54%时,茎向的mRNA转移率最高(3.66%),在46%~48%时,根向的mRNA转移率最高(4.71%)。(3)统计13个嫁接体的共转移mRNA发现,分别有1032和1727个mRNA在至少2个嫁接组合中进行了茎向和根向的长距离转移,主要参与了碳代谢、氨基酸合成、信号转导等过程。其中5个和2个m RNA在7个嫁接组合中分别进行了茎向和根向的长距离转移,主要参与了激素转运及基础代谢等过程。【结论】异源嫁接植物中的mRNA转移与mRNA长度、GC含量等密切相关,也与基因功能及作用位置相关。异源植物间的m RNA差异和交流,赋予了嫁接植物新的表型。

[Objective] This paper intends to analyze the mobile mRNA in heterologous grafted plants,explore the effects of sequence and functional characteristics on mRNA transfer, reveal the principle of m RNA transfer, and provide a theoretical basis for the directional regulation of grafting. [Method] With the transcriptome data of the various grafts, the coding region length and GC content of transfer mRNAs were calculated by Tbtools software and their correlation with mRNA transfer was further analyzed by Excel software. The sequence identity analysis via BLASTP was applied to find out the co-transfer mRNAs in different grafts. Function annotation and metabolic pathways analysis of the mRNAs were conducted through GO and KEGG database. [Result](1) The average length of root-to-shoot or shoot-to-root transfer m RNA was 1 573 and 1 547, respectively. The mRNA transfer ratio increased progressively along with the m RNA length increasing. Obviously, the transfer ratio of the root-to-shoot mRNA was larger than that of the shoot-to-root mRNAs, and the tendency was more significant with the mRNA length increasing.(2) When the GC content was 52%-54%, the mRNA transfer rate from stem to root was the highest(3.66%), and when the GC content was 46%-48%, the mRNA transfer rate from root to stem was the highest(4.71%).(3) Co-transfer mRNA analysis showed 1 032 root to shoot and 1 727 shoot to root mRNA were present in at least 2 grafts, which mainly participated in carbon metabolism, amino acid synthesis, and signal transduction. Even, 5 root-to-shoot mRNA and 2 shoot-to-root mRNA were commonly present in 7 grafts that mainly involved in hormone transport and basic metabolism. [Conclusion] mRNA transfer in heterologous grafted plants is closely related to mRNA length, GC content, gene function and action position. mRNA differences and exchanges between heterologous plants give grafted plants new phenotypes.