Analysis Of The Pleiotropic Effect Of Cucumber Carpel Gene CsCLAVATA3 Regulating Fruit Development By Near-isogenic Lines

Carpel number is one of the important factors affecting cucumber fruit development.Cucumber carpel number gene CsCLAVATA3(CsCLV3)plays an important role in increasing single fruit weight and improving commercial characters of cucumber fruit.In order to explore the genetic effects of CsCLV3 on fruit development,flower development,seed development and plant morphology of cucumber,‘Changchun Mici’(CCMC)and ‘Jinchun 4’(JC4)were used as donor parents to construct a near-isogenic line(NIL),to analyze the genetic background of 3 carpel homozygous and 5 carpel homozygous plants by SSR and GBS sequencing.The number of cucumber carpels(CN),length of commercial melon(FL),thickness of commercial melon(FD),shape index of commercial melon(FSI),weight of commercial melon(FW),dry weight of fruit(FDW),length of mature fruit(MFL),diameter of mature fruit(MFD),mature fruit shape index(MFSI),mature fruit weight(MFW),mature fruit diameter(MFD),mature fruit shape index(MFSI),mature fruit weight(MFW),Melon neck length(FNL),peduncle length(FPL),pulp thickness(FTH),seed chamber size(SCS),seed number(SN),seed length(SL),seed width(SW),seed 100-seed weight(100SW),Internode length(IL),vine diameter(VD),node number(NN),female flower initial flowering time(FFT),male flower petal number(MPN),The pistil logarithmic(STN)and the number of female petals(FPN)were analyzed by phenotype analysis and QTL location analysis.The main results of the study are as follows:1.One near-isogenic line with CCMC background and one near-isogenic line with JC4 background were successfully constructed.In the two NIL,the CsCLV3 gene infiltration fragments were located at the position of D1(10.8Mb)associated with the number of carpels on chromosome 1.The results of SSR analysis were consistent with SNP analysis,and the other infiltration fragments were randomly distributed,which had nothing to do with the target gene and had little background noise,so they could be used in genetic effect analysis.2.The phenotypic values of 3 carpel homozygote and 5 carpel homozygote in 2 NIL showed bimodal distribution except NN and FNL,which accorded with Mendel’s separation law at 1:1,and each character was significantly correlated with the number of carpels.In NIL,CN,FD,FW,FDW,MFD,MFW,FPL,SCS,SN,VD,FFT,MPN,STN and FPN of 5 carpel homozygous type were higher than those of 3 carpel homozygous type,while FL,FSI,MFL,MFSI,FTH,SL,SW,100 SW and IL were lower than the latter.3.In JT lines,except NN and FNL,QTL of MPN,MFSI,CN,FSI,IL,SCS,STN,MFW,VD,FTH,FW,SW,MFD,SN,FPN,FDW,MFL,SL,FD,FPL,100 SW,FL,FFT were located on chromosome 1linked marker D1.The contribution rates of legacy transmission were 84.2%,80%,75%,73.7%,56.3%,45.5%,45.2%,44.8%,35.6%,33.3%,32.4%,32%,30.7%,29%,28%,27.5%,23.2%,21.9%,15.9%,15.6%,14%,10.6% and 9.9%,respectively.In CT lines,the QTL,genetic contribution rates of MFSI,CN,100 SW,FSI,MFD,SN,MFW,SL,FL,MFL,SW and FD were 99.3%,95.3%,93.9%,92.8%,89.7%,87.9%,83.2%,80.3%,57%,55.2%,53% and 36.4%,respectively.This study showed that CsCLV3 had multiple regulation effects on MPN,MFSI,CN,FSI,IL,SCS,STN,MFW,VD,FTH,FW,SW,MFD,SN,FPN,FDW,MFL,SL,FD,FPL,100 SW,FL and FFT while regulating the number of cucumber carpels.The results has great significance for breeding high-yield germplasm while using CSCLV3 gene.