Transcriptome and Physiological Analysis of Rootstock Types and Silicon Affecting Cold Tolerance of Cucumber Seedlings

Abstract

Cucumbers grafted on rootstocks with different wax-removing abilities show varying levels of cold tolerance. The content of pericarp wax powder correlates with its silicon-metabolizing capacity, and rootstock grafting can alter not only the cold tolerance but also the silicon-metabolizing capacity of the scion. The molecular mechanisms responsible for resistance due to rootstocks and silicon and the pathway that affects cold tolerance, however, remain poorly understood. Therefore, we performed physiological and transcriptome analysis to clarify how rootstock types and silicon affect cold tolerance in cucumber seedlings. Then, we randomly selected eight differentially expressed genes (DEGs) for quantitative real time PCR (qRT-PCR) analysis to proof the reliability of the transcriptome data. The results showed that silicon can enhance the cold tolerance of cucumbers by boosting the phenylpropanoid metabolism, and rootstock grafting can boost the active oxygen scavenging ability and synthesis level of hormones in cucumbers and maintain the stability of the membrane structure to enhance cold tolerance. The difference in cold tolerance between the two rootstocks is because the cold-tolerant one has stronger metabolic and sharp signal transduction ability and can maintain the stability of photosynthesis, thereby contributing to the stability of the cellular system and enhancing tolerance to cold.

WRKY41/WRKY46-miR396b-5p-TPR module mediates abscisic acid-induced cold tolerance of grafted cucumber seedlings

“…Grafting is one of the most commonly used techniques in vegetable crop production, which can improve stress tolerance, yield, and quality of vegetables ( Shi et al, 2019 ; Wei et al, 2019 ; Darre et al, 2022 ). In recent years, many studies have shown that the cold tolerance of vegetable crops can be improved by grafting onto tolerant rootstock by maintaining higher photosynthesis, enhancing antioxidant activity to scavenge excess reactive oxygen species (ROS) ( Xu et al, 2016 ; Lu J. et al, 2022 ; Luan et al, 2022 ), but information regarding the molecular mechanism of grafting in increasing cold tolerance remains largely unknown. In this study, we found that cucumber seedlings grafted onto figleaf gourd significantly increased the tolerance to cold stress through promoting the accumulation of ABA to induce the expression of WRKY41 and WRKY46 , which further activated the expression of miR396b-5b to target cleavage of TPR .…”

Integrated transcriptome and DNA methylome analysis reveal the biological base of increased resistance to gray leaf spot and growth inhibition in interspecific grafted tomato scions

“…Several studies have shown that grafting in vegetables can significantly reduce diseases and environmental risks, especially in successive cropping systems [ 8 ]. In Cucurbitaceae family, pumpkins are used as rootstocks to enhance cold tolerance in cucumber seedlings by boosting the phenylpropanoid metabolism and phytohormones synthesis [ 9 ]. The use of resistant rootstocks in Rosaceae family reveals high resistance of apple scions to apple specific replant disease [ 10 ].…”

Silicon and Potassium-Induced Modulations in Leaf Carbohydrate Metabolism Confer Freezing Tolerance in Satsuma Mandarin

“…Si affects a variety of plant physiological activities, including photosynthetic rate, stomatal conductance, water use efficiency, stomatal size and number, transpiration rate, and the hydraulic conductance of roots in many crops [33,34]. The ameliorative effect of Si against freezing has been reported in numerous crops, including grapes [35], mangoes [36], cucumber [37], tomato [38], barley [39], wheat [40], alfalfa [41] and turfgrass [42]. Potassium (K) is another major element in plants that plays an important role in mitigating different abiotic stresses such as drought, heat, and cold [43,44].…”