Genome-wide characterization of sugarcane catalase gene family identifies a ScCAT1 gene associated disease resistance

Authors: WU, QIBIN - Fujian Agriculture And Forest University; CHEN, YANLING - Fujian Agriculture And Forest University; ZOU, WENHUI - Fujian Agriculture And Forest University; Pan, Yong-Bao; LIN, PEIXIA - Fujian Agriculture And Forest University; XU, LIPING - Fujian Agriculture And Forest University; GRISHAM, MICHAELP - Retired ARS Employee; DING, QIUGANG - Fujian Agriculture And Forest University; SU, YACHUN - Fujian Agriculture And Forest University; QUE, YOUXIONG - Fujian Agriculture And Forest University

Submitted to: International Journal of Biological Macromolecules
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 1/18/2023
Publication Date: 1/23/2023
Citation: Wu, Q., Chen, Y., Zou, W., Pan, Y.-B, Lin, P., Xu, L., Grisham, M.P., Ding, Q., Su, Y., Que, Y. 2023. Genome-wide characterization of sugarcane catalase gene family identifies a ScCAT1 gene associated disease resistance. International Journal of Biological Macromolecules. 232:123398. https://doi.org/10.1016/j.ijbiomac.2023.123398.
DOI: https://doi.org/10.1016/j.ijbiomac.2023.123398

Interpretive Summary: When plants are affected by different environmental stresses, catalase (CAT) enzymes are activated to remove excessive free radicals from cells. This helps the plants maintain normal growth and development. Many comprehensive reports on CAT enzymes are available from other plant species, but none is available from sugarcane. In this study, the recently published genetic code of a wild relative of sugarcane, Saccharum spontaneum (Ss), was examined and five gene sequences encoding for 16 CAT proteins were identified. Based on similarities in protein structure, 16 proteins were divided into 3 subfamilies that shared eight similar structures, including genes for three amino acids, one active catalytic site, one heme-ligand signature sequence, and three PTS1 (peroxisomal targeting signal 1) sequence. Several other sequences that affect the expression of genes involved in sugarcane’s stress response were identified. The CAT genes were differentially expressed in various tissues and under cold, drought, and smut disease infection. Two chemical tests, namely, RT-qPCR and CAT enzyme activity, showed that CAT activity increased when sugarcane was infected with smut. In addition, the CAT1 gene was introduced to three tobacco lines to validate its role in disease resistance. The results demonstrated that this gene enhanced the resistance of transgenic tobacco to disease infection by removing excessive free radicles in the plant. This paper provides comprehensive information for sugarcane CAT genes and sets up a basis for the identification of CAT gene function in sugarcane under stress.

Technical Abstract: In plants, catalase (CAT) mainly scavenges H2O2 from reactive oxygen species (ROS) and regulates the growth and development in response to various environmental stresses. So far, a complete and systematic genome-wide identification of CAT gene family in Saccharum has not yet been reported. Here, 16 SsCAT proteins encoded by five SsCAT genes were identified based on a Saccharum spontaneum genome. The SsCAT proteins were clustered into three subfamilies, and genes with closer homology shared similar gene structures with conserved motifs. Most SsCAT proteins contained three conserved amino acids, one active catalytic site, one heme-ligand signature sequence, and three peroxisomal targeting signal 1 (PTS1) sequences. The cis-regulatory elements predicted in the promoters revealed that SsCAT genes were involved in growth and development in response to various hormones and stresses. RNA-Seq databases showed that SsCAT genes were differentially expressed in Saccharum tissues and under cold, drought, and Sporisorium scitamineum stresses. RT-qPCR and CAT enzyme activity assay showed that the ScCAT1 gene transcript (GenBank accession number KF664183) and relevant CAT activity were up-regulated under S. scitamineum stress. In addition, three T3 generation transgenic lines of Nicotiana benthamiana were obtained that overexpressed the sugarcane ScCAT1 gene. The results of disease resistance function validation demonstrated that ScCAT1 gene could enhance the resistance of N. benthamiana to infection by Pseudomonas solanacearum and Fusarium solani var. coeruleum through scavenging of excessive toxic ROS and up-regulated expressions of genes related to hypersensitive response (HR), ROS and salicylic acid (SA) pathways. This study provides comprehensive information for the CAT gene family and sets up a basis for its function identification under abiotic and biotic stresses in sugarcane.