Anil Grover

Professor & Head of the Department

Specializations: Rice Heat Stress Biology



Specialization:Rice Heat Stress Biology


Research Interests

The threat of climate change to agriculture is showing its effects. For breeding plants with superior heat tolerance ability by genetic methods, it is important to decipher the cellular processes that contribute in plant heat tolerance. ClpB-C/Hsp100 chaperone protein represents the protein disaggregation machinery of the cells. Hsp101 transcript/ protein are strongly upregulated by heat stress. Our work is focused on the following aspects of Arabidopsis and rice Hsp101 proteins: 

  1. We wish to understand the transcriptional basis of OsHsp101 (Os05g44340) induction under heat stress. Rice genome sequence has 25 OsHsf genes including 13 class A, 8 class B and 4 class C members. Yeast one-hybrid assays showed us that OsHsfA6a specifically interacts with OsHsp101 promoter. Using several deletion constructs, high transactivation potential of OsHsfA6a was mapped to its C-terminal domain. Role of post-translational modifications especially phosphorylation in regulating the activity of OsHsfA6a was highlighted. Interactors of OsHsfA6a were identified by library scale screening and are being analysed for their functional significance on OsHsp101 gene expression. 
  2. In respect of Arabidopsis Hsp101 (At1g74310), we noted that salk_087844 mutant (hx mutant) lacks expression of 6 tandem genes. The hx seedlings possess significantly higher basal thermotolerance as compared to wild type, Col-0 seedlings. hsc70-1 mutation emerged as the major player in causing higher basal thermotolerance phenotype of the hx line.  The complementation of hx mutant with Hsc70-1 genomic region rescued the Col-0 like phenotype while the over-expression of genome fragment of Hsc70-1 in Col-0 background resulted in higher sensitivity of the transgenic lines to heat stress. Hsp101 transcript and protein levels were conspicuously higher especially during non-heat stress and post-heat stress recovery conditions in hx seedlings. We propose that Hsc70-1 is a negative regulator affecting HsfA1d/A1e/A2 activators which in turn regulate Hsp101 expression and basal thermotolerance. 
  3. To optimize the genetic expression of Hsp101 in transgenic Arabidopsis plants for enhancing its heat tolerance phenotype, four constructs made were CaMV35 promoter driven AtHsp101 cDNA (CaMV35S:AtHsp101construct), CaMV35S promoter driven OsHsp101 cDNA (CaMV35S:OsHsp101 construct), AtHsp101 promoter driven-OsHsp101 cDNA (AtHsp101p:OsHsp101construct) and with AtHsp101 genome fragment  (AtHsp101-genomic fragment construct). Wild type (WT) Arabidopsis plants transformed with CaMV35S:OsHsp101 construct (C lines) showed equal or more sensitive phenotype under HS than the WT seedlings. Hsp101 protein levels were mostly lower in transgenic C lines than the WT seedlings. Under HS, WT Arabidopsis plants transformed with AtHsp101p:OsHsp101construct (IN lines) showed increased AtHsp101 transcript and protein amounts as well as higher heat tolerant phenotype of the seedlings as against the WT seedlings. In case of WT Arabidopsis plants transformed with AtHsp101-genomic fragment construct (GF lines), two kinds of progenies were noted. Most lines (11 out of 14) showed over-expression of AtHsp101 transcript and protein and showed more heat tolerant phenotype than the WT seedlings. Hsp101 transcript and protein in 3 lines out of 14 (GF3-5, GF7-3 and GF53-6 lines) were drastically impaired, and these lines were overly sensitivity to HS. 


Select Publications

  1. Sarkar NK, S Kotak, M Agarwal, Y-K Kim and A Grover. 2020. Silencing of Class I small heat shock proteins affects seed-related attributes and thermotolerance in rice seedlings. Planta 251:26.
  2. Lavania D, A Dhingra, A Grover. 2018. Analysis of transactivation potential of rice (Oryza sativa L.) heat shock factors. Planta247: 1267-1276.
  3. Singh G, NK Sarkar and A Grover. 2018. Mapping of domains of heat stress transcription factor OsHsfA6a responsible for its transactivation activity. Plant Science 274: 80-90.
  4. Mishra RC and A Grover. 2016. ClpB/Hsp100 proteins and heat stress tolerance in plants. Critical Reviews in Biotechnology36: 862-874.
  5. Mishra RC and A Grover. 2014. Intergenic sequence between Arabidopsis ClpB-C/Hsp100 and choline kinase genes functions as a heat inducible bidirectional promoter. Plant Physiology 166: 1646-1658.
  6. Sarkar NK, Y-K Kim and A Grover. 2014. Coexpression network analysis associated with call of rice seedlings for encountering heat stress. Plant Molecular Biology 84: 125-143. 
  7. Singh A, U Singh, D Mittal and A Grover. 2010. Genome-wide analysis of rice ClpB/HSP100, ClpC and ClpD genes. BMC Genomics 11: 95.
  8. Singh A and A Grover. 2010. Plant Hsp100/ClpB-like proteins: poorly-analyzed cousins of yeast ClpB machine. Plant Molecular Biology 74: 395-404.
  9. Sarkar NK, K Yeon-Ki and A Grover. 2009. Rice sHsp genes: genomic organization and expression profiling under stress and development. BMC Genomics 10:393.
  10. Katiyar_Agarwal S, M Agarwal and A Grover. 2003. Heat tolerant basmati rice engineered by overexpression of hsp101 gene. Plant Molecular Biology 51: 677-686.
  11. Agarwal M, C Sahi, S Katiyar-Agarwal, S Agarwal, T Young, DR Gallie, VM Sharma, K Ganesan and A Grover. 2003. Molecular characterization of rice Hsp101: Complementation of yeast hsp104 mutation by disaggregation of protein granules and differential expression in indica and japonica rice types Plant Molecular Biology 51: 543-553.
  12. Agarwal M, S Katiyar-Agarwal, C Sahi, DR Gallie and A Grover. 2001. Arabidopsis thaliana Hsp100 protein: kith and kin. Cell Stress and Chaperones 6: 219-224. 
  13. Singla SL, A Pareek, AK Kush and A Grover. 1998. Distribution patterns of the 104 kDa stress-associated protein in rice Plant Molecular Biology 37: 911-919.
  14. Pareek A, SL Singla and A Grover. 1995. Immunological evidence for accumulation of two novel 104 and 90 kDa HSPs in response to diverse stresses in rice and in response to high temperature stress in diverse plant genera. Plant Molecular Biology 29: 293-301.
  15. Singla SL and A Grover.  1993. Antibodies raised against a yeast heat shock protein cross-react with a heat and abscisic acid- regulated polypeptide in rice. Plant Molecular Biology 22: 1177-1180.