Abstract

The existence of salinity stress can be traced well before the domestication of crops, but the documentation and mitigation of this menace started only 100 years ago. Due to the unavailability of appropriate equipment and lack of sophisticated techniques, the salinity appraisal of soils and crop injury at early times was done visually. Initially, the major focus of scientists was on reclamation and management of salt-affected soils to render them fit for agriculture. Later, they strived to assess the degree of salt tolerance of different plant species using growth and morphological traits as well as some fundamental physiological criteria, most importantly ion uptake, and accumulation. In the early 20th century, the idea of developing salt tolerant crops, as an alternative to soil reclamation was realized, and the terms “biological fix” or in general “biological approach” were coined. This triggered plant breeders to initiate breeding programs aimed at developing salt tolerant crop cultivars. Although conventional selection and breeding has several limitations, mainly its slowness, it has yielded many salt tolerant lines and cultivars of different crops. To speed up the crop breeding programs, a genetic engineering approach referred to as “transgenic approach” was introduced during the late 20th century. Plant biotechnologists have produced large numbers of transgenic lines of different crops however their use in developing salt tolerant cultivars is not remarkable. Furthermore, genetically modified (GM) crops are prohibited in many countries because of putative health risks and biosafety concerns. More recently, for precise editing of genomes of organisms, new molecular tools have been developed. For example, CRISPR-Cas9 is being used to precisely edit genes involved in abiotic stress tolerance, including salt tolerance. Its success in terms of developing cultivars tolerant to multiple stresses including salt stress is expected.

摘要

盐分胁迫的存在可以追溯到作物驯化之前，但这种威胁的记录和缓解仅在 100 年前才开始。由于缺乏合适的设备和缺乏成熟的技术，早期的土壤盐分评估和作物伤害是通过目视进行的。最初，科学家的主要关注点是开垦和管理受盐分影响的土壤，以使其适合农业。后来，他们努力使用生长和形态特征以及一些基本的生理标准（最重要的是离子吸收和积累）来评估不同植物物种的耐盐程度。在 20 世纪初，开发耐盐作物作为土壤复垦的替代方案的想法得到了实现，并且创造了术语“生物修复”或一般的“生物方法”。这促使植物育种者启动了旨在开发耐盐作物品种的育种计划。尽管传统的选择和育种有一些局限性，主要是它的缓慢，但它已经产生了许多耐盐品系和不同作物的品种。为了加快作物育种计划，在 20 世纪后期引入了一种称为“转基因方法”的基因工程方法。植物生物技术人员已经生产了大量不同作物的转基因品系，但它们在开发耐盐栽培品种方面的应用并不显着。此外，由于假定的健康风险和生物安全问题，许多国家禁止转基因（GM）作物。最近，为了精确编辑生物的基因组，已经开发出新的分子工具。例如，CRISPR-Cas9 正被用于精确编辑涉及非生物胁迫耐受性的基因，包括耐盐性。预计它在开发耐受包括盐胁迫在内的多种胁迫的品种方面取得成功。