Growth and transpiration of soybean genotypes with HaHB4® transcription factor for drought tolerance

Abstract

The expression of HaHB4 ® transcription factor reduces soybean sensitivity to abiotic stresses, such as water deficit. Studies that quantify the tolerance of HaHB4 ® soybean to the soil water content in comparison with cultivars currently sown in Brazil are lacking.The objective of this study was to determine the level of drought tolerance of soybean genotypes expressing the HaHB4 ® transcription factor (TS18-6-610108 and TS18-6-610084) and commercial cultivars (TMG 7063 IPRO and BS IRGA 1642 IPRO) subjected to water deficit during the vegetative phase. We used the fraction of transpirable soil water (FTSW) approach. Parameters related to leaf transpiration, dry matter accumulation, water use efficiency (WUE), and transpiration coefficient (TC) were evaluated in the four soybean genotypes and two treatments (T1-100% replacement of transpired water and T2-without replacement of transpired water). The FTSW threshold for the decline in transpiration was evaluated to identify the onset of water stress in soybean. TS18-6-610108 and BS IRGA 1642 IPRO maintains potential transpiration at low FTSW values. The TS18-6-610108 genotype has 14% higher WUE than the sensitive cultivar under water deficit. Under well-irrigated conditions, the HaHB4 ® genotypes showed the highest TC values, which indicate well-functioning physiological processes.

Sowing date and maturity group in soybean grown in lowlands

“…Only MG 4.8 without irrigation responded differently, having a higher LAI when sown in November (Figure 3A). In addition to MG 4.8 having the cycle considered short for the region when submitted at an early sowing (October) in the lowlands and without irrigation, a small water deficit caused a reduction in the growth rate, which led to a drop in the LAI (Winck et al, 2022). The LAI under the irrigated condition (Figure 3), except for the January sowing, which was higher than the optimal LAI (6.3) to achieve high yields (Tagliapietra et al, 2018).…”

“…The evolution of the node number (Figure 4) and the final node number (FNN) (Figure 4A) showed a similarity between the irrigated and the non-irrigated experiments in the October sowing, due to regular precipitation in the vegetative phase, which did not compromise the development of the cultivars (Figure 1). With the occurrence of water deficit, plants use strategies to minimize this stress, ranging from stomatal closure under small stresses and evolving until stopping growth and development in case of more severe stress (Winck et al, 2022). In Figure 3 it can be seen that the water deficit caused the reduction of LAI by the production of abscisic acid, during all periods of sowing.…”

Genome-Wide Identification and Characterization of Copper Chaperone for Superoxide Dismutase (CCS) Gene Family in Response to Abiotic Stress in Soybean

“…Abiotic stress, such as drought, high salinity, low and high temperature, heavy metals can seriously affect the normal growth and development of plants, especially the yield of crops. Drought stress can reduce the productivity of soybean by interfering with physiological and biochemical processes such as photosynthesis, translocation, respiration, and growth stimulants [ 1 , 2 ]. During a prolonged drought stress condition, reaction oxygen species (ROS) accumulate excessively and cause oxidative damage.…”

Raising crops for dry and saline lands: Challenges and the way forward

“…Several articles report the results of gene overexpression in crop plants. For example, the overexpression of the HaHB4 transcription factor in soybean (Minussi Winck et al, 2022) and the CaPDZ1 gene in chickpea (Lande et al, 2022) confers drought tolerance. Moreover, the overexpression of OsCYP2‐P , which encodes an active cyclophilin, conferred salinity tolerance in rice by maintaining ion homeostasis and preventing membrane damage (Roy et al, 2022).…”