A late embryogenesis abundant protein HVA1 regulated by an inducible promoter enhances root growth and abiotic stress tolerance in rice without yield penalty

Abstract

Summary Regulation of root architecture is essential for maintaining plant growth under adverse environment. A synthetic abscisic acid (ABA)/stress‐inducible promoter was designed to control the expression of a late embryogenesis abundant protein (HVA1) in transgenic rice. The background of HVA1 is low but highly inducible by ABA, salt, dehydration and cold. HVA1 was highly accumulated in root apical meristem (RAM) and lateral root primordia (LRP) after ABA/stress treatments, leading to enhanced root system expansion. Water‐use efficiency (WUE) and biomass also increased in transgenic rice, likely due to the maintenance of normal cell functions and metabolic activities conferred by HVA1 which is capable of stabilizing proteins, under osmotic stress. HVA1 promotes lateral root (LR) initiation, elongation and emergence and primary root (PR) elongation via an auxin‐dependent process, particularly by intensifying asymmetrical accumulation of auxin in LRP founder cells and RAM, even under ABA/stress‐suppressive conditions. We demonstrate a successful application of an inducible promoter in regulating the spatial and temporal expression of HVA1 for improving root architecture and multiple stress tolerance without yield penalty.

Production of cut sunflower under water volumes and substrates with coconut fiber

“…The decrease from T2 (67%) to T1 (33%), characterizing higher level of water stress, compromised the roots more intensely than the shoots, causing an increase in the ratio to 13.66. A mild drought can make the plant to exhibit such adaptive response, which allows reduction in transpiration and increase in water absorption, whereas a severe drought usually reduces the growth of both (Chen et al, 2015). On the other hand, the behavior of this ratio between T3 (100%) and T4 (133%) appears to result from losses of nutrients by leaching with the excess water in T4, which may have collaborated to the limitation of shoot growth and stimulus to root growth in order to increase the absorption of nutrients, also leading to the reduction in shoot/root ratio.…”

The major‐effect quantitative trait locus Fnl7.1 encodes a late embryogenesis abundant protein associated with fruit neck length in cucumber

“…For example, SAG21 ( AtLEA5 , At4g02380 ) encodes a mitochondria‐localized LEA protein; its antisense lines exhibit reduced primary root lengths, while overexpression lines show longer root hairs (Salleh et al , ). The rice gene HVA1 , which encodes a group 3 small LEA protein, promotes primary and lateral root elongation through the regulation of signalling and homeostasis of auxin and abscisic acid (Chen et al , ). Here, the LEA‐encoding gene CsFnl7.1 was responsible for increased FNLs in cucumber fruit, and this may represent a novel function for this protein family.…”

Drought and heat stress-related proteins: an update about their functional relevance in imparting stress tolerance in agricultural crops

“…Considering the above facts, it is clear that a single LEA protein can perform multiple functions; for example, the chloroplastic LEA protein (COR15am) and the mitochondrial Group 3 proteins (LEAM) are engaged in protecting both membranes and proteins. In rice, a LEA protein, (HVA1) stimulated root induction and multiple stress resilience through ABA/stress inducible promoter (Chen et al 2015b). Similarly, Group 3 LEA proteins located in the vacuole of citrus assisted in ion sequestration and exhibited antioxidant as well as nucleic acid binding ability (Pedrosa et al 2015).…”