Expression of a rice soluble starch synthase gene in transgenic wheat improves the grain yield under heat stress conditions
There are many environmental factors that limit productivity of crop plants and excessive heat is no exception. For example, wheat, a cool season crop, is particularly susceptible to heat stress during the grain fill period of its growth stage. For every 1 °C rise in temperature above its optimum temperature range (15-22°C), yield potential is reduced by 5-7%. This reduction is due in large part to loss of activity of heat-labile soluble starch synthase I, an enzyme that converts glucose to starch in the seed endosperm. Funded by Kansas wheat producers through the Kansas Wheat Commission, this paper describes the results of expressing a heat tolerant version of the starch soluble synthase gene from rice in transgenic wheat. Experimental data from growth chamber heat stress assays show yield can be increased up 34% compared to non-transgenic controls. This paper suggests that the engineering of a heat tolerant soluble starch synthase gene can be a potential strategy to improve crop yield under heat stress conditions.
Bin Tian, Shyamal K. Talukder, Jianming Fu, Allan K. Fritz, and Harold N. Trick. Expression of a rice soluble starch synthase gene in transgenic wheat improves the grain yield under heat stress conditions. In Vitro Cellular & Developmental Biology-Plant, 54: 216–227, 2018.
The initial hours of post-excision light are critical for adventitious root regeneration from Arabidopsis thaliana (L.) Heynh. cotyledon explants
Many plant genotypes are recalcitrant, suffering from low rates of organ regeneration. Furthermore, researchers have commonly noted the frustrations of experiencing highly variable rates of plant organ regeneration, even within a single genotype. In the art associated with plant tissue culture, researchers are sometimes encouraged to work in near darkness. Combining these observations, the Raizada lab at the University of Guelph in Canada hypothesized that short periods of deliberate or inadvertent light exposure of explants may decrease plant organ regeneration in vitro. The Lab previously tested this hypothesis with respect to shoot regeneration (Plant Cell & Environment 36: 68-86). Now, the researchers report a parallel study involving root regeneration from Arabidopsis thaliana cotyledon explants exposed to darkness/light for different durations. In a 1-month regeneration protocol, the study has revealed that exposure of new explants to moderate light for only a few hours was associated with declines in root regeneration frequency, thus defining a critical early light period. Genetic mutants and chemical inhibitors were used to identify modulators of this light-induced response. The results show that this critical early period of 48 hours is regulated by complex interactions involving light, photoreceptor signaling, reactive oxygen species, photoprotective pigments, and auxin. Combined, these two studies demonstrate the importance of maintaining consistent light exposure during the early stages following generating plant tissue culture explants. Furthermore, the study reveals candidate genetic signaling pathways underlying this light-dependent response for potential future genetic selection or chemical intervention.
M. Blair Nameth, Travis L. Goron, Stephen J. Dinka, Adam Morris, Jenny English, Dorrett Lewis, Rosalinda Oro, Manish N. Raizada. The initial hours of post-excision light are critical for adventitious root regeneration from Arabidopsis thaliana (L.) Heynh. cotyledon explants. In Vitro Cellular & Developmental Biology – Plant, 54:273–290, 2018.