Knockdown of an inflorescence meristem-specific cytokinin oxidase - OsCKX2 in rice reduces yield penalty under salinity stress condition.
Cytokinins play a significant role in determining grain yield in plants. Cytokinin oxidases catalyse irreversible degradation of cytokinins and hence modulate cellular cytokinin levels. Here, we studied the role of an inflorescence meristem-specific rice cytokinin oxidase - OsCKX2 - in reducing yield penalty under salinity stress conditions. We utilized an RNAi-based approach to study the function of OsCKX2 in maintaining grain yield under salinity stress condition. Ultra-performance liquid chromatography-based estimation revealed a significant increase in cytokinins in the inflorescence meristem of OsCKX2-knockdown plants. To determine if there exists a correlation between OsCKX2 levels and yield under salinity stress condition, we assessed the growth, physiology and grain yield of OsCKX2-knockdown plants vis-à-vis the wild type. OsCKX2-knockdown plants showed better vegetative growth, higher relative water content and photosynthetic efficiency and reduced electrolyte leakage as compared with the wild type under salinity stress. Importantly, we found a negative correlation between OsCKX2 expression and plant productivity as evident by assessment of agronomical parameters such as panicle branching, filled grains per plant and harvest index both under control and salinity stress conditions. These results suggest that OsCKX2, via controlling cytokinin levels, regulates floral primordial activity modulating rice grain yield under normal as well as abiotic stress conditions.
Plant Stress Biology, International Centre for Genetic Engineering and Biotechnology, New Delhi, 110 067, India.
Rohit
R
Joshi
Plant Stress Biology, International Centre for Genetic Engineering and Biotechnology, New Delhi, 110 067, India.
Khirod Kumar
KK
Sahoo
Plant Stress Biology, International Centre for Genetic Engineering and Biotechnology, New Delhi, 110 067, India.
Amit Kumar
0000-0002-4624-7282
AK
Tripathi
Plant Stress Biology, International Centre for Genetic Engineering and Biotechnology, New Delhi, 110 067, India.
Ritesh
R
Kumar
Plant Stress Biology, International Centre for Genetic Engineering and Biotechnology, New Delhi, 110 067, India.
Brijesh Kumar
BK
Gupta
Stress Physiology and Molecular Biology Laboratory, School of Life Sciences, Jawaharlal Nehru University, New Delhi, 110067, India.
Ashwani
0000-0002-2923-0681
A
Pareek
Plant Stress Biology, International Centre for Genetic Engineering and Biotechnology, New Delhi, 110 067, India.
Sneh Lata
0000-0002-0521-2622
SL
Singla-Pareek
D003583:Cytokinins / Q000378:metabolism*; D002523:Edible Grain; D055785:Gene Knockdown Techniques; D056626:Inflorescence / Q000201:enzymology / Q000235:genetics / Q000254:growth & development / Q000502:physiology; D018519:Meristem / Q000201:enzymology / Q000235:genetics / Q000254:growth & development / Q000502:physiology; D012275:Oryza / Q000201:enzymology* / Q000235:genetics / Q000254:growth & development / Q000502:physiology; D010088:Oxidoreductases / Q000235:genetics / Q000378:metabolism*; D010937:Plant Growth Regulators / Q000378:metabolism*; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism; D054712:Salinity; D000077323:Salt Stress
D003583:Cytokinins; D010937:Plant Growth Regulators; D010940:Plant Proteins; D010088:Oxidoreductases; C019984:cytokinin oxidase
RNAi; panicle branching; salt stress; spikelet number; yield gap