Genome-wide Identification Of Wheat F-box Family And Expression Analysis Of TaFBL14 And TaSKP2A Related To Stress Resistance

F-box family is one of the largest protein families in plants,and widely involved in many biological processes,such as growth and development,self-incompatibility,senescence and biotic/abiotic stresses.The F-box family has been characterized early and thoroughly in model plants Arabidopsis and rice.But less was known for F-box family in wheat---an important cereal crop due to the poor conservation of the F-box gene family and the complicated and polyploid wheat genome.Therefore,there is an urgent need to carry out a systematic characterization and functional studies for wheat F-box family.Based on this situation,this study conducted a comprehensive genome-wide analysis of the systematic identification,classification,structural analysis,evolutionary relationships and chromosome distribution of the wheat F-box family.Moreover,tissue-specific expression and response to abiotic stress of wheat F-box family members were investigated by digital PCR.TaFBL14and TaSKP2A previously obtained from our lab team were used as the research target genes to discuss their expression patterns under treatment with 3 hormones and 2 abiotic stresses.Chitinase interacting with TaSKP2A was obtained by Yeast two-hybrid.Main findings are as follows:1.1013 potential F-box proteins encoded by 406 genes were identified in the wheat genome,which were divided into 12 subfamilies based on their C-terminal domains.The wheat F-box proteins are50-1088 aa in length with MWs of 5.76-120.84 kDa.Prediction of the theoretical pIs indicates a wide pH value range from 4.09 to 12.01,more F-box proteins are alkaline.Subcellular localization predictionshowed that most of F-box proteins were located in the nucleus.The 406 F-box genes were unevenly distributed on 21 wheat chromosomes.Segmental duplication was the main reason for the increase in the number of wheat F-box genes.Tissue-speciffic expression revealed that most F-box genes are highly expressed in the late developmental stage of wheat,including the formation of spikes,seeds and flag leaves.Transcriptome analysis of wheat treated by heat and drought stresses indicated that the F-box genes were involved in response to 2 stresses and their combination.2.The TaFBL14gene was up-regulated by induction of SA,ABA and MeJAin wheat TcLr15,and it's expression reached to thepeak at 6-12 h after treatment by 3 hormones,and then went back to the similar level of the control?0 h?.TaFBL14was mainly affected by NaCl treatment,and showed a trends of increasing first and then decreasing,the highest expression was 6 h after treatment by NaCl,while no or less difference was observed in wheat treated by H₂O₂,PEG and distilled water,which showed that TaFBL14was less affected by H₂O₂ and drought stresses.The TaSKP2A gene was only induced by SA treatment for 24 h in TcLr15,the transcript was 2.6 times higner than that of 0 h,the transcripts at other timepoints keep similar level with that of 0 h,also no obviuous transcript changes after treatment by ABA and MeJA at all tested timepoints.After treatment with NaCl,TaSKP2A strongly up-regulated at 48 h,no diference was observed among samples treated at other timepoint and control?0h?.TaSKP2A showed a decline expression after treatment with H₂O₂ and droughtstresses.3.10 candidate proteins interacting with TaFBL14and 11 with TaSKP2A were obtained by screening yeast strain AH109 cDNA library?TcLr15 inoculated with avirolent leaf rust strain 05-19-43??.According to our research object,3 proteins including peroxidase 51-Like?POD?,chitinase 2?CHI?and profilin-1?PRO?,were further testified by constructing AD-prey vector,then hybrid with BD-bait.Protein interaction existed between TaSKP2A and chitinase,and they may play their roles via SCF complex.The present study carried out a systematic research for wheat F-box family at the first time,which supply a startpoint for further dissection the functions of F-box family in wheat growth,development and response to biotic/abiotic stresses.