Characterization of Seed Proteome Profile of Wild and Cultivated Chickpeas of India
Authors: Dhar Santanu , Bhattacharjee Mamta , Baishya Debabrat , Acharjee Sumita 
Published: September 2020

Background:
Chickpea is a widely grown legume in India, Australia, Canada, and
Mediterranean regions. Seeds of chickpea are good source of protein for both human and animals.
Wild relatives of chickpea (Cicer arietinum) are the potential gene pool for crop improvement;
however, very little information is available on the seed proteome of these wild chickpeas.

Objective:
We aimed to analyze the seed proteome profiles of three wild relatives of chickpea, Cicer
bijugum, Cicer judaicum and Cicer microphyllum along with two cultivated varieties JG11 and
DCP 92/3.

Method:
Total seed proteins were extracted using various extraction buffers for 2-D gel electrophoresis.
Protein separated in a 2-D gels were subjected to image analyses, differentially expressed
proteins were extracted from the gels and identified by the MALDI TOF/TOF. Seed protease
inhibitors were analysed biochemically.

Results:
We have standardized the 2-D gel electrophoresis method and separated seed proteins using
the modified method. We identified a large number (400) of protein proteins which were differentially
expressed in cultivated and wild type species of chickpea. A comparative analysis between
C. bijugum and JG 11 revealed the presence of 9 over-expressed and 22 under-expressed proteins,
while the comparison between C. bijugum with DCP 92/3 showed 8 over-expressed and 18 under--
expressed proteins. Similarly, comparative analysis between C. microphyllum with DCP 92/3
showed 8 over-expressed proteins along with 22 under-expressed proteins, while the comparative
study of C. microphyllum with JG11 displayed 9 over-expressed and 24 under-expressed proteins.
We also compared C. judaicum with DCP 92/3 which revealed 15 overexpressed and 11 under-expressed
proteins. On the other hand, the comparative analysis of C. judaicum with JG11 showed 10
over-expressed proteins, while the numbers of under-expressed proteins were 14. Among the differentially
expressed protein proteins, 19 proteins were analyzed by the MS/MS, and peptides were
identified using the MASCOT search engine. In the wild relatives the differentially expressed proteins
are phosphatidylinositol 4-phosphate 5- kinase, β-1-6 galactosyltransferase, RNA helicase,
phenyl alanine ammonia lyase 2, flavone 3’-0-methyl transferase, Argonaute 2, Myb related protein,
Tubulin beta-2 chain and others. The most important one was legumin having α- amylase inhibition
activity which was up regulated in C. bijugum. We also studied the activity of protease inhibitor
(trypsin and α- amylase inhibitors) in these seed lines which showed differential activity of
protease inhibitors. The highest trypsin and α- amylase inhibition was observed in C. judaicum and
C. bijugum, respectively.

Conclusion:
The differentially expressed proteins of wild relatives of chickpea appeared to be involved
in various metabolic pathways. The study provides us information about the differences in
the seed proteome of these wild species and cultivated varieties for the first time.