Genome-wide identification and characterization of heat shock factor genes from pigeonpea (<i>Cajanus cajan</i>)

Abstract

Genome-wide analysis of heat shock factor ( H s f ) g e n e s was ca r r ied out in p i g e on p e a ( Cajanus cajan ) in order to understand their structure and function. A tot a l of 23 Hsfs w e r e p re dict e d using FGENESH a nd l a b e led a s C c Hsf . Out of the 2 3 g e n e s, 14 unique sequences w e r e s e l ec t e d a nd c h a r a c t er i z e d for t h e ir p re sumed str u c tur e s s u c h a s p r ote i n doma in a nd mo t if o r g a ni z a t i on. The p h y l o g e n e t ic r e lationships a nd e x p re ss i on p r o f i l ing of C cHsf g e n e s under heat-stress w as studied. Phylogenetic analysis showed that CcH s f g e n e s w e r e di s t r i b ut e d i n to eight g r o u p s. I n th i s st u d y , c lasses A, B, and C were f u r ther subdivi d e d in t o subcl a sses such a s A1, A2, A 3, A4, A5, A6, A8, A 9, B1, B 2, B 3 , B 4 and C1. E x p r e ss i on p r o f ili n g of all 14 genes w a s ca r r i e d out by s e m i - q u a nt i ta t ive P CR, among which C c H sfA - 1d and C c HsfA - 2 w e r e observed to be highly upregulated duri n g heat-stress . R e l a t i ve qu a nt i f i ca t i on with qRT- P C R showed that C cHsfA - 1d i s up r e g ul a t e d 2 - 6 h r s af t e r heat-stress indicating its significant role as an early response factor. Our study provides a glimpse of the Hsf gene family in pigeonpea and this information can be utilized to gain more insight into the heat-response mechanism in pigeonpea. Abbreviations: AHA - Aromatic/ Hydrophobic /Acidic; Hsf - Heat Shock Factors; IRRK- Isoleucine, Arginine, Arginine, Lysine; NLS - Nuclear Localization Signal; NES - Nuclear Export Signal