Differential Evolution Patterns Of The Cellulose Synthase Gene Superfamily In Eudicots And Monocots

Herbal energy plants are one of the most promising biomass resources,and cellulose-rich herbal energy plants are very convenient for large-scale planting and industrialization.Therefore,it is important to study the cellulose synthase gene family for herbaceous plants.More than two-thirds of the species of angiosperms studied in this study were herbs.Therefore,studying the evolutionary pattern of the cellulose synthase gene in monocots and dicots can also reflect its evolutionary characteristics in herbaceous plants.We constructed a phylogenetic tree using cellulose synthase genes family from 57 fully sequenced angiosperm genomes.Then we analyzed the different evolutionary patterns of the cellulose synthase gene in Eudicots and Monocots.We found that the cellulose synthase gene can be clearly divided into three categories in the angiosperm,named ?,?,? respectively.The CesA is included in Class ?.Class ? includes CslD,CslF;Class ? includes CslH,CslE,CslJ,and CslG.The identification and analysis of composition distribution of motifs revealed that ?,?,and ? have two specific motifs,respectively.This result supports the conclusion of being divided into three categories.With Amborella trichopoda and Nymphaea alba-based angiosperms as exo-groups,CesA can be further divided into 8 subfamilies.They are named CesAl to CesA8;CslD can be further divided into 5 subfamilies,named CslD1 to CslD5.That is,the cellulose synthase family can be divided into 18 categories in angiosperms.At the same time,we found that the reasons for the amplification of the cellulose synthase gene in the three classes ?,?,and ? are different.Among them,the class ? cellulose synthetase genes are amplified in angiosperms due to the occurrence of genome-wide replication events within a family;CslF cellulose synthase Genes in Class ? are amplified by a large number of tandem replication events both early and recent in Poaceae;CslD1 was mainly due to gene amplification resulting from monocots and eudicots whole genome replication events;In class ?,the cellulose synthetase genes have monocots and eudicots whole genome replication events only in the CslE class.The other categories are mainly due to the occurrence of tandem replication events within a single species and gene amplification resulting from tandem replication events within a family.At the same time,we also found that although there was no significant difference in the number of genes between herbaceous plants and woody plants,there were more gene amplifications of herbaceous plants in different classifications than woody plants.The selection pressure of the cellulose synthase gene superfamily was analyzed by Easy codeml software.Using the branch model first,we found that the cellulose synthase gene of woody plants has a higher evolutionary rate than herbs.The lower dN:dS value of the herb indicates that the cellulose synthase is in a relatively stable state during evolution,while the cellulose synthesis enzyme in the woody plant has a fast evolution rate and new functionalization may occur.However,the dN:dS values of the individual clades are low.Therefore,we further studied the evolutionary characteristics of different branches of the cellulose synthase gene superfamily using the branch site model.We find that whether it is in CesA,CslD or CslH/E/J/G,the significant sites of Gramineae and the other four families are mainly found in the three families in which herb plants are concentrated.Among them,the largest is Gramineae.Based on the distribution of these significant sites,we speculated that many of these amino acids located in the catalytic domain have undergone major changes during evolution,and that herbaceous plants have been altered at more selective sites than woody plants.In summary,there is no significant difference in the number of cellulose synthetase genes between herbaceous plants and woody plants,mainly because herbaceous plants have significantly more selective pressure sites than woody plants.This shows that the difference between the cellulose and woody cellulose synthetase is mainly at the site of the difference rather than the number of genes.