Table_1_Distinctive Traits for Drought and Salt Stress Tolerance in Melon (Cucumis melo L.).DOCX

Melon (Cucumis melo L.) is a crop with important agronomic interest worldwide. Because of the increase of drought and salinity in many cultivation areas as a result of anthropogenic global warming, the obtention of varieties tolerant to these conditions is a major objective for agronomical improvement. The identification of the limiting factors for stress tolerance could help to define the objectives and the traits which could be improved by classical breeding or other techniques. With this objective, we have characterized, at the physiological and biochemical levels, two different cultivars (sensitive or tolerant) of two different melon varieties (Galia and Piel de Sapo) under controlled drought or salt stress. We have performed physiological measurements, a complete amino acid profile and we have determined the sodium, potassium and hormone concentrations. This has allowed us to determine that the distinctive general trait for salt tolerance in melon are the levels of phenylalanine, histidine, proline and the Na+/K+ ratio, while the distinctive traits for drought tolerance are the hydric potential, isoleucine, glycine, phenylalanine, tryptophan, serine, and asparagine. These could be useful markers for breeding strategies or to predict which varieties are likely perform better under drought or salt stress. Our study has also allowed us to identify which metabolites and physiological traits are differentially regulated upon salt and drought stress between different varieties.

甜瓜（Cucumis melo L.）是全球范围内具有重要农艺价值的栽培作物。由于人为活动引发的全球变暖导致诸多栽培区域的干旱与盐胁迫加剧，培育耐逆品种已成为农艺性状改良的核心目标之一。明确胁迫耐受性的限制因子，有助于确立通过传统育种或其他技术手段改良的目标与性状方向。基于此目标，本研究在生理与生化层面，对两个甜瓜品种（Galia与Piel de Sapo）的两份不同种质（分别为敏感型与耐受型）在可控干旱及盐胁迫条件下进行了系统表征。我们开展了生理指标测定、全氨基酸谱分析，并检测了钠、钾离子及激素含量。研究结果表明，甜瓜盐耐受性的核心共性特征为苯丙氨酸、组氨酸、脯氨酸含量及Na+/K+比值；而干旱耐受性的标志性性状则包括水势、异亮氨酸、甘氨酸、苯丙氨酸、色氨酸、丝氨酸与天冬酰胺水平。上述指标可作为育种策略的有效筛选标记，或用于预测不同品种在干旱与盐胁迫环境下的表现优劣。本研究同时明确了不同甜瓜品种在盐胁迫与干旱胁迫下，代谢物与生理性状的差异调控模式。