Carillo Petronia
Dipartimento di Scienze e Tecnologie Ambientali, Biologiche e Farmaceutiche, Università degli Studi della Campania "Luigi Vanvitelli", Caserta, Italy.
Front Plant Sci. 2018 Feb 2;9:100. doi: 10.3389/fpls.2018.00100. eCollection 2018.
Plant responses to salinity are complex, especially when combined with other stresses, and involve many changes in gene expression and metabolic fluxes. Until now, plant stress studies have been mainly dealt only with a single stress approach. However, plants exposed to multiple stresses at the same time, a combinatorial approach reflecting real-world scenarios, show tailored responses completely different from the response to the individual stresses, due to the stress-related plasticity of plant genome and to specific metabolic modifications. In this view, recently it has been found that γ-aminobutyric acid (GABA) but not glycine betaine (GB) is accumulated in durum wheat plants under salinity only when it is combined with high nitrate and high light. In these conditions, plants show lower reactive oxygen species levels and higher photosynthetic efficiency than plants under salinity at low light. This is certainly relevant because the most of drought or salinity studies performed on cereal seedlings have been done in growth chambers under controlled culture conditions and artificial lighting set at low light. However, it is very difficult to interpret these data. To unravel the reason of GABA accumulation and its possible mode of action, in this review, all possible roles for GABA shunt under stress are considered, and an additional mechanism of action triggered by salinity and high light suggested.
植物对盐胁迫的反应很复杂，尤其是当与其他胁迫同时存在时，这涉及基因表达和代谢通量的许多变化。到目前为止，植物胁迫研究主要仅采用单一胁迫方法。然而，植物同时暴露于多种胁迫下（一种反映现实情况的组合方法），由于植物基因组与胁迫相关的可塑性以及特定的代谢修饰，会表现出与对单一胁迫的反应完全不同的特定反应。从这个角度来看，最近发现，仅在盐胁迫与高硝酸盐和高光同时存在时，硬粒小麦植株中积累的是γ-氨基丁酸（GABA）而不是甘氨酸甜菜碱（GB）。在这些条件下，与低光下处于盐胁迫的植株相比，这些植株表现出更低的活性氧水平和更高的光合效率。这当然很重要，因为大多数针对谷物幼苗进行的干旱或盐胁迫研究都是在可控培养条件下的生长室中以及设置为低光的人工光照下进行的。然而，很难解释这些数据。为了阐明GABA积累的原因及其可能的作用方式，在本综述中，考虑了胁迫下GABA分流的所有可能作用，并提出了由盐胁迫和高光触发的另一种作用机制。
