Department of Vegetable Crops, Faculty of Agriculture, Cairo University, PO box 12613, Giza, Egypt.
Department of Genetics, Faculty of Agriculture, Cairo University, PO box 12613, Giza, Egypt.
BMC Plant Biol. 2022 Aug 20;22(1):408. doi: 10.1186/s12870-022-03791-7.
Water scarcity is a major limiting factor for crop yield production in arid and water-stressed areas worldwide. Cucumber plants have a high transpiration ratio and are vulnerable to drought. Grafting commercial genotypes onto selected strong rootstocks has been useful in mitigating the effects of drought. Therefore, this study aimed to evaluate the possibility of using a novel rootstock plant's tolerance to water-deficit stress in inducing drought tolerance in cucumbers by activating the stress-response gene expression and the antioxidant system, which improved the cucumber quality and yield under water-deficit conditions. This field experiment was conducted for > 2 years, 2020 and 2021, with five drought stress tolerant genotypes (i.e., rootstock) and drought-sensitive genotype Luerans (i.e., a scion). They were subjected to various deficit irrigation levels for 12 days, and their agro-physiological and molecular responses to water-deficit stress were assessed. The results of the study showed that the agronomical parameters, including the leaf area (LA), leaf water content (LWC), number of leaves, plant height, root dry matter shoot dry matter, rates of leaf appearance and stem elongation, and total yield significantly increased with grafted cucumber plants than with non-grafted cucumber plants (control) under normal and stressful conditions.Similar results were observed in the physiological measurements in terms of antioxidant enzymes, abscisic acid levels, gibberellic acid content, and lower lipid peroxidation (malondialdehyde, MDA). Grafting of Luerans (section) on five rootstocks significantly raised the activity of antioxidant enzymes (catalase and peroxidase), improved the gibberellic acid and proline accumulation, and reduced the content of lipid peroxidation and abscisic acid. Furthermore, the real-time polymerase chain reaction expression results revealed that transcript levels of the stress-response genes CsAGO1 and CsDCLs increased rapidly and continuously in five rootstock grafting. Concurrently, these findings suggest that grafting with local varieties of novel drought-tolerant rootstock genotypes could improve drought tolerance in drought-sensitive cucumber genotypes.
水资源短缺是全球干旱和水资源紧张地区作物产量的主要限制因素。黄瓜植株蒸腾比率高，易受干旱影响。将商业基因型嫁接到选定的强砧木上，有助于减轻干旱的影响。因此，本研究旨在评估利用新型砧木植物对水分亏缺胁迫的耐受性，通过激活胁迫响应基因表达和抗氧化系统，在水分亏缺条件下诱导黄瓜耐旱性的可能性，从而提高黄瓜的品质和产量。本田间试验进行了超过 2 年，即 2020 年和 2021 年，使用了 5 种耐旱基因型（即砧木）和耐旱敏感基因型 Luerans（即接穗）。它们接受了不同程度的亏缺灌溉 12 天，并评估了它们对水分亏缺胁迫的农艺和分子响应。研究结果表明，在正常和胁迫条件下，与未嫁接的黄瓜植株（对照）相比，嫁接的黄瓜植株的农艺参数（包括叶面积、叶水含量、叶片数、株高、根干物质、茎干物质、叶片出现率、茎伸长率和总产量）显著增加。在抗氧化酶、脱落酸水平、赤霉素含量和较低的脂质过氧化（丙二醛、MDA）方面也观察到类似的生理测量结果。将 Luerans（节）嫁接到 5 种砧木上，显著提高了抗氧化酶（过氧化氢酶和过氧化物酶）的活性，增加了赤霉素和脯氨酸的积累，降低了脂质过氧化和脱落酸的含量。此外，实时聚合酶链反应表达结果显示，五种砧木嫁接后，胁迫响应基因 CsAGO1 和 CsDCLs 的转录水平迅速且持续增加。同时，这些发现表明，与当地新型耐旱砧木基因型的品种嫁接可以提高耐旱敏感黄瓜基因型的耐旱性。
