Arabidopsis GDH1 and GDH2 genes double knock-out results in a stay-green phenotype during dark-induced senescence

• Published in: Physiology and molecular biology of plants 2024-10, Vol.30 (10), p.1631-1642
• Main Authors: Garnik, Elena Yu, Vilyanen, Daria V., Vlasova, Anfisa A., Tarasenko, Vladislav I., Konstantinov, Yuri M.
• Format: Article
• Language: English
• Subjects: Arabidopsis; Biological and Medical Physics; Biomedical and Life Sciences; Biophysics; Cell Biology; Chlorophyll; chlorophyll b reductase; color; Darkness; death; Degradation; Dehydrogenase; Environmental degradation; Genes; Glutamate dehydrogenase; Leaves; Life Sciences; Mutants; phenotype; Phenotypes; Plant Physiology; Plant Sciences; Plants; Reductases; Research Article; Senescence; Yellowing
• ISSN: 0971-5894; 0974-0430
• DOI: 10.1007/s12298-024-01517-7

Yellowing is the first visually observable sign of plant leaf senescence. We found that Arabidopsis double knockout mutant gdh1gdh2 for genes of NAD(H)-dependent glutamate dehydrogenase retains green color of the leaves (stay-green phenotype) during a dark-induced senescence, in contrast to wild-type plants, whose leaves turn yellow. When the gdh1gdh2 plants are exposed to the dark more than four days, they demonstrate slower chlorophyll degradation than in the wild-type plants under the same conditions, as well as dysregulation of chlorophyll breakdown genes encoding chlorophyll b reductase, Mg-dechelatase, pheophytinase and pheophorbide a oxygenase. The slowed degradation of chlorophyll b in gdh1gdh2 plants significantly alters the chlorophyll a / b ratio. Ion leakage in the mutant plants increases significantly from four to eight days in the darkness, correlating with their premature death during this period. The discovered facts suggest a functional connection between activity of NAD(H)-dependent glutamate dehydrogenase and dark-induced senescence progress in Arabidopsis.