The Mechanism Of GmPAPS1 Gene Regulating Soybean Stem Twining Growth Habit

The transition of twining growth wild soybeans(Glycine soja Sieb.& Zucc.)to up-right growth cultivated soybeans(Glycine max [L.] Merr.)is a critical step of soybean domestication.Up-right architecture not only notably enhance planting density and boost group yield significantly,but also extremely facilitate harvesting action.Howevre the genetic and metabolic bases underlying this distinctive trait are mainly unclear.In this research,we isolated and characterized soybean mutant sc3755 with twining stem.According to genetic mapping we confirmed poly(A)polymerase functional defective is responsible for altered phenotype.Additonaly,twining or upright growth habit are most likely caused by different genotypes.1.The mutation of GmPAPS1 is responsible for the twisting stem in sc3755 mutantTwining mutant sc3755 was isolated from soybean mutant bank(Glycine.Max ssp Williams 82)generated through EMS treatment(Laboratory based).The sc3755 mutant display an extremity extend internode length,thinner stem diameter and right-hand twisted stem just resemble to wild soybean.The genetic authenticate demonstrate the alteration are aroused by a single recessive nuclear gene.Via mapping on F2 population from a cross between sc3755 and He Dou12 and resequencing we confirmed Glyma.09g179500 is our target gene which located on chromosome 9.Glyma.09g179500 encodes a poly(A)polymerase and named it GmPAPS1.Hybridization with two other allelic mutants,all F1 generation show a mutant phenotype;transgenic knockout on GmPAPS1 in wild type show a mutant phenotype;overexpression the sense recombinant plasmid of GmPAPS1 in sc3755 background rescued the mutant phenotype.These result additionally proved GmPAPS1 is the target gene.2.Microtube associate m RNAs polyadenylation process have been affected due to the mutation of GmPAPS1Cellular examination reveal in transverse section the cell size shrinking could be the reason of thinner stem;in longitudinal section different layter cell length increased in discrepant level might be the reason of twist and extend internode.Further micro observation manifest sc3755 mutant show a thicker cell wall,irregular cell wall surface and unorganized microtube array.These results indicate microtube and cell wall alteration causing cell morphology and arrangement change leading to twist stem.Transcriptome differently expressed genes KEGG pathway enrichment and GO enrichment analysis reveals a bulk of cell wall synthesis and microtubule organization genes exhibit enrich signal in sc3755 mutant.Further poly(A)tail length detect assay manifest Gm UTG44,Gm UTG21,Gm SPRL1,Gm Chit B and Gm EXLB5 polyadenylation process are affected.The mutants phenotype are most likely result from irregular expression of those genes which are caused by abnormal polyadenylation.3.Different GmPAPS1 haplotype give rise to different stem growth habitAfter analysis 302 soybean resequencing data,genotype polymorphism of GmPAPS1 significantly reduced in landrace or improved cultivar compared with wild soybean.The gene located in a selective sweep region which subjected to a relative higher selective pressure far more beyond top 5% of whole genome degree.When comparing resequencing GmPAPS1 to reference genome,there are totally 53 SNPs and 8 In Dels are found.Haplotype scanning result indicate there are 104 haplotype exist,while the first four occupy the largest group.Coincidentally these tour haplotype separated twist and up-right stem.Thus we speculate a portion of vertical selection is achieved through screening specific GmPAPS1 haplotype.