Overexpression of AtNCED3 gene improved drought tolerance in soybean in greenhouse and field conditions
Mayla Daiane Corrêa Molinari, Renata Fuganti‐Pagliarini, Silvana Regina Rockenbach Marin, Leonardo César Ferreira, Daniel de Amorim Barbosa, Juliana Marcolino-Gomes, M. C. N. de Oliveira, Liliane Márcia Mertz-Henning, Norihito Kanamori, Hironori Takasaki, Kaoru Urano, Kazuo Shinozaki, Kazuo Nakashima, Kazuko Yamaguchi‐Shinozaki, Alexandre Lima Nepomuceno
Abstract
Water deficit is an important climatic problem that can impair agriculture yield and economy. Genetically modified soybean plants containing the AtNCED3 gene were obtained aiming drought-tolerance improvement. The NCED3 gene encodes a 9-cis-epoxycarotenoid dioxygenase (NCED, EC 1.13.11.51), an important enzyme in abscisic acid biosynthesis. ABA activates the expression of drought-responsive genes, in water-deficit conditions, targeting defense mechanisms and enabling plants to survive under low water availability. Results from greenhouse experiments showed that the transgene AtNCED3 and the endogenous genes GmAREB1, GmPP2C, GmSnRK2 and GmAAO3 presented higher expression under water deficit (WD) in the event 2Ha11 than in WT-plants. No significant correlation was observed between the plant materials and WD conditions for growth parameters; however, gas exchange measurements decreased in the GM event, which also showed 80% higher intrinsic water use when compared to WT plants. In crop season 2015/16, event 2Ha11 showed higher total number of pods, higher number of pods with seeds and yield than WT plants. ABA concentration was also higher in GM plants under WD. These results obtained in field screenings suggest that AtNCED3 soybean plants might outperform under drought, reducing economic and yield losses, thus being a good candidate line to be incorporated in the soybean-breeding program to develop drought-tolerant cultivars.