AUTHOR=Rizwan Hafiz Muhammad , Shaozhong Fang , Li Xiaoting , Bilal Arshad Muhammad , Yousef Ahmed Fathy , Chenglong Yang , Shi Meng , Jaber Mohammed Y. M. , Anwar Muhammad , Hu Shuai-Ya , Yang Qiang , Sun Kaiwei , Ahmed Mohamed A. A. , Min Zheng , Oelmüller Ralf , Zhimin Lin , Chen Faxing 

TITLE=Genome-Wide Identification and Expression Profiling of KCS Gene Family in Passion Fruit (Passiflora edulis) Under Fusarium kyushuense and Drought Stress Conditions

JOURNAL=Frontiers in Plant Science

VOLUME=Volume 13 - 2022

YEAR=2022

URL=https://www.frontiersin.org/journals/plant-science/articles/10.3389/fpls.2022.872263

DOI=10.3389/fpls.2022.872263

ISSN=1664-462X

ABSTRACT=Plant and fruit surfaces are covered with cuticle wax and provide a protective barrier against biotic and abiotic stresses. It consists of very-long-chain fatty acids (VLCFAs) and their derivatives. β-Ketoacyl-CoA synthase (KCS) is a key enzyme in the synthesis of VLCFAs and provides a precursor for the synthesis of cuticle wax. In the present study, we identified thirty-two KCS genes in the passion fruit (Passiflora edulis) genome and phylogenetically grouped them into four main groups as KCS1-like, FAE1-like, FDH-like, and CER6-like and eight subgroups. All identified 31 PeKCS genes were positioned on seven chromosomes, while PeKCS32 was localized to the unassembled genomic scaffold. The cis-element analysis provides insight into the possible role of PeKCS genes in phytohormones and stress responses. Syntenic analysis revealed that gene duplication played a crucial role in the expansion of the PeKCS gene family and underwent a strong purifying selection. All PeKCS proteins shared similar 3D structures, and a protein-protein interaction network was predicted with known Arabidopsis proteins. Further, twenty putative ped-miRNAs were also predicted that belong to 9 families targeting thirteen PeKCS genes, while the ped-miR166 family targeted up to four PeKCS genes. GO and KEGG annotation results showed that PeKCS genes were highly associated with fatty acid synthase and elongase activity, lipid metabolism, stress responses, and plant-pathogen interaction. ERF, MYB, Dof, C2H2, TCP, LBD, NAC, and bHLH plant TFs were found to be highly enriched in PeKCS genes. qRT-PCR expression analysis showed that most PeKCS genes were highly upregulated in leaves but not stem and roots tissues under drought stress conditions compared with controls. Notably, most PeKCS genes were upregulated at 9th dpi under F. kyushuense biotic stress condition but not at 12th dpi compared to controls. This study provides a basis for further understanding the functions of KCS genes, improving wax and VLCFA biosynthesis, and improvement of passion fruit resistance.