Genome-wide identification and expression analysis of the MADS gene family in sweet orange (Citrus sinensis) infested with pathogenic bacteria

Xiuyao Yang; Mengjie Zhang; Dengxian Xi; Tuo Yin; Ling Zhu; Xiujia Yang; Xianyan Zhou; Hanyao Zhang; Xiaozhen Liu

doi:10.7717/peerj.17001

Genome-wide identification and expression analysis of the MADS gene family in sweet orange (Citrus sinensis) infested with pathogenic bacteria

PeerJ. 2024 Feb 29:12:e17001. doi: 10.7717/peerj.17001. eCollection 2024.

Authors

Xiuyao Yang^#¹, Mengjie Zhang^#¹, Dengxian Xi¹, Tuo Yin¹, Ling Zhu¹, Xiujia Yang¹, Xianyan Zhou², Hanyao Zhang¹, Xiaozhen Liu¹

Affiliations

¹ Southwest Forestry University, Kunming, China.
² Institute of Tropical and Subtropical Economic Crops, Institute of Tropical and Subtropical Economic Crops, Yunnan Academy of Agricultural Sciences, Ruili, China.

^# Contributed equally.

Abstract

The risk of pathogenic bacterial invasion in plantations has increased dramatically due to high environmental climate change and has seriously affected sweet orange fruit quality. MADS genes allow plants to develop increased resistance, but functional genes for resistance associated with pathogen invasion have rarely been reported. MADS gene expression profiles were analyzed in sweet orange leaves and fruits infested with Lecanicillium psalliotae and Penicillium digitatum, respectively. Eighty-two MADS genes were identified from the sweet orange genome, and they were classified into five prime subfamilies concerning the Arabidopsis MADS gene family, of which the MIKC subfamily could be subdivided into 13 minor subfamilies. Protein structure analysis showed that more than 93% of the MADS protein sequences of the same subfamily between sweet orange and Arabidopsis were very similar in tertiary structure, with only CsMADS8 and AG showing significant differences. The variability of MADS genes protein structures between sweet orange and Arabidopsis subgroups was less than the variabilities of protein structures within species. Chromosomal localization and covariance analysis showed that these genes were unevenly distributed on nine chromosomes, with the most genes on chromosome 9 and the least on chromosome 2, with 36 and two, respectively. Four pairs of tandem and 28 fragmented duplicated genes in the 82 MADS gene sequences were found in sweet oranges. GO (Gene Ontology) functional enrichment and expression pattern analysis showed that the functional gene CsMADS46 was strongly downregulated of sweet orange in response to biotic stress adversity. It is also the first report that plants' MADS genes are involved in the biotic stress responses of sweet oranges. For the first time, L. psalliotae was experimentally confirmed to be the causal agent of sweet orange leaf spot disease, which provides a reference for the research and control of pathogenic L. psalliotae.

Keywords: Biotic stress; Expression analysis; L. psalliotae; Sweet orange mads gene.

MeSH terms

Amino Acid Sequence
Arabidopsis* / genetics
Bacteria
Candy
Citrus sinensis* / genetics
Humans

Grants and funding

The study is supported by the Rural Revitalization Science and Technology Project-Rural Revitalization Industry Key Technology Integration demonstration Project (202304BP090005), the Yunnan Academician (expert) Workstation Project (202305AF150020), the Agricultural Joint key projects in Yunnan Province (202301BD070001-003), and the National Natural Science Foundation of China (Grant No. 31760450). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.