Finger Fernando L, Eide John D, Lafta Abbas M, Khan Mohamed F R, Dogramaci Munevver, Fugate Karen K
Departamento de Agronomia, Universidade Federal de Viçosa, Viçosa, MG, Brazil.
Edward T. Schafer Agricultural Research Center, USDA-ARS, Fargo, ND, United States of America.
PeerJ. 2021 Jun 17;9:e11623. doi: 10.7717/peerj.11623. eCollection 2021.
Sugarbeet ( L.) roots are stored under conditions that cause roots to dehydrate, which increases postharvest losses. Although exogenous jasmonate applications can reduce drought stress in intact plants, their ability to alleviate the effects of dehydration in postharvest sugarbeet roots or other stored plant products is unknown. Research was conducted to determine whether jasmonate treatment could mitigate physiological responses to dehydration in postharvest sugarbeet roots.
Freshly harvested sugarbeet roots were treated with 10 µM methyl jasmonate (MeJA) or water and stored under dehydrating and non-dehydrating storage conditions. Changes in fresh weight, respiration rate, wound healing, leaf regrowth, and proline metabolism of treated roots were investigated throughout eight weeks in storage.
Dehydrating storage conditions increased root weight loss, respiration rate, and proline accumulation and prevented leaf regrowth from the root crown. Under dehydrating conditions, MeJA treatment reduced root respiration rate, but only in severely dehydrated roots. MeJA treatment also hastened wound-healing, but only in the late stages of barrier formation. MeJA treatment did not impact root weight loss or proline accumulation under dehydrating conditions or leaf regrowth under non-dehydrating conditions. Both dehydration and MeJA treatment affected expression of genes involved in proline metabolism. In dehydrated roots, proline dehydrogenase expression declined 340-fold, suggesting that dehydration-induced proline accumulation was governed by reducing proline degradation. MeJA treatment altered proline biosynthetic and catabolic gene expression, with greatest effect in non-dehydrated roots. Overall, MeJA treatment alleviated physiological manifestations of dehydration stress in stored roots, although the beneficial effects were small. Postharvest jasmonate applications, therefore, are unlikely to significantly reduce dehydration-related storage losses in sugarbeet roots.
甜菜（Beta vulgaris L.）根在导致脱水的条件下储存，这会增加采后损失。虽然外源茉莉酸处理可以减轻完整植株的干旱胁迫，但它们减轻采后甜菜根或其他储存植物产品脱水影响的能力尚不清楚。开展研究以确定茉莉酸处理是否能减轻采后甜菜根脱水的生理反应。
将刚收获的甜菜根用10 μM茉莉酸甲酯（MeJA）或水处理，并在脱水和非脱水储存条件下储存。在储存的八周内，研究处理后根的鲜重、呼吸速率、伤口愈合、叶片再生和脯氨酸代谢的变化。
脱水储存条件增加了根的重量损失、呼吸速率和脯氨酸积累，并阻止了根冠处叶片的再生。在脱水条件下，MeJA处理降低了根的呼吸速率，但仅在严重脱水的根中。MeJA处理还加速了伤口愈合，但仅在屏障形成的后期。MeJA处理在脱水条件下不影响根的重量损失或脯氨酸积累，在非脱水条件下不影响叶片再生。脱水和MeJA处理均影响脯氨酸代谢相关基因的表达。在脱水根中，脯氨酸脱氢酶表达下降了340倍，表明脱水诱导的脯氨酸积累是通过减少脯氨酸降解来控制的。MeJA处理改变了脯氨酸生物合成和分解代谢基因的表达，在非脱水根中影响最大。总体而言，MeJA处理减轻了储存根中脱水胁迫的生理表现，尽管有益效果较小。因此，采后施用茉莉酸不太可能显著减少甜菜根中与脱水相关的储存损失。
