Abstract

Flood in rice fields at the time of seed sowing and early seedling establishment causes extensive crop loss due to the inability of the seeds to tolerate and overcome submergence. In the present study, rice genotypes from Assam, India tolerant to hypoxia during germination were identified through systematic screening of deep-water rice genotype collection from flood-prone ecosystem of Brahmaputra river valley. The difference in tolerance to hypoxia during germination within the species provides scope for identification of novel hypoxia-responsive factors involved in tolerance as mechanism of tolerance may not be conserved across tolerant gennplasms. Tolerant genotypes were further subjected to physiological and molecular characterization. Growth rate kinetics in tolerant genotypes new Rangdhakekua bao (RKB) and cultivar Khao Hlan On (KHO) from International Rice Research Institute (IRRI) used as positive control exhibited stronger escape strategy under hypoxic condition compared to sensitive genotype IR-64 (negative control). Activities of a-amylase and pyruvate decarboxylase were significantly higher in RKB and KHO than in IR-64, while no significant difference was observed in the alcohol dehydrogenase activity. Reverse transcription quantitative PCR confirmed increased amounts of transcripts of sucrose nonfermenting I related protein kinase, myeloblastosis-related protein S1, rice amylase 3D, and trehalose phosphate phosphatase 7 genes, which are known to be involved in hypoxia signaling cascade. Besides, transcription factors (TFs) like ethylene responce factors 71 and 63, ethylene insensitive 3-like la and proteins like cxpansins A7 and A2, which are involved in cell elongation had also significantly higher amounts in RKB compared to IR64. Additional factors that include TFs like ERF71 and FRF63 that shows perturbation at transcription even within tolerant genotypes might constitute the genotype-specific regulation, evolved as a part of its adaptive mechanism to survive under submerged conditions.

Keywords

alpha-amylase; anaerobic germination; Oryza sativa; pyruvate decarboxylase; transcription factors

Published in

Biologia Plantarum
2020, Volume: 64, pages: 244-252
Publisher: ACAD SCIENCES CZECH REPUBLIC, INST EXPERIMENTAL BOTANY

SLU Authors

• Kumar, Dhananjay

  • Department of Plant Breeding, Swedish University of Agricultural Sciences
    
  • Assam Agricultural University (AAU)

UKÄ Subject classification

Agricultural Science


Publication identifier

DOI: https://doi.org/10.32615/bp.2019.128

Permanent link to this page (URI)

https://res.slu.se/id/publ/105291