Exploration and Genome-wide Profiling of the Arabinogalactan Protein Gene Family Across the Chickpea Genome (Cicer arietinum)

Abstract

 Chickpea (Cicer arietinum) is agriculturally vital due to its nutrition and economic 
value. Grasping its growth mechanisms is key to better yields. Chimeric Arabinogalactan Proteins 
(AGPs), glycoproteins in plant cells' matrix, have a protein core wrapped in carbohydrates. These 
distinct AGPs are crucial for plant physiology, affecting cellular processes like division, 
differentiation, and expansion, and aiding pollen tube growth. Beyond their core role, AGPs have 
biotech and agriculture potential, improving yields and stress resistance by affecting cellular 
functions. Understanding AGPs' plant role could revolutionize productivity and sustainability amid 
changing environments. Using bioinformatics tools, we successfully identified 69 chickpea genes, 
encompassing 27 CaXYLP, 19 CaFLA, and 23 CaELA genes. Each gene exhibited distinct 
conserved domains characteristic of its respective gene family. To ensure naming consistency, we 
re-designated the CaXYLP, CaFLA, and CaELA genes based on their genuine orthologs in rice 
and Arabidopsis. Interestingly, most of these genes shared common cis-regulatory elements, 
responding to factors such as abscisic acid, auxin, salicylic acid, jasmonic acid, drought, and light. 
Our gene duplication analysis uncovered that all identified paralogous genes originated from 
segmental duplications (SD). Conversely, Phytocyanin-like AGPs exhibited maximum expression 
during seed, embryo, and various flower development stages. Lastly, Fasciclin-like AGPs reached 
their zenith expression in seeds and root hairs. These analyses collectively emphasize the pivotal 
role of chimeric AGPs in augmenting crop productivity and bolstering stress resilience, while also 
revealing novel regulatory mechanisms in plant growth and development.