Gould Nick, Thorpe Michael R, Taylor Joe T, Boldingh Helen L, McKenzie Catherine M, Reglinski Tony
The New Zealand Institute for Plant and Food Research Limited, 412 No 1 Road, RD 2, Te Puke 3182, New Zealand.
IBG-2: Plant Sciences, Forschungszentrum Jülich, D-52425 Jülich, Germany.
Plants (Basel). 2021 Nov 8;10(11):2406. doi: 10.3390/plants10112406.
This work aims to understand how (Chardonnay) vines prioritise the export and distribution of recently fixed photoassimilate between root tissue, fruit, and defence, following the elicitation of a defence response. Jasmonic acid (JA) and its methyl ester, MeJA, are endogenous plant hormones, known collectively as jasmonates, that have signalling roles in plant defence and consequently are often used to prime plant defence systems. Here, we use exogenous jasmonate application to mature source leaves of Chardonnay grapevines to elucidate the prioritisation strategy of carbon allocation between plant defence and growth. Our results demonstrate that jasmonate application to Chardonnay leaves can elicit a defence response to but the effect was localised to the jasmonate-treated area. We found no evidence of a systemic defence response in non-treated mature leaves or young growing tissue. JA application reduced the photosynthetic rate of the treated leaf and reduced the export rate of recently fixed carbon-11 from the leaf. Following JA application, a greater proportion of available recently fixed carbon was allocated to the roots, suggesting an increase in sink strength of the roots. Relative sink strength of the berries did not change; however, an increase in berry sugar was observed seven days after JA treatment. We conclude that the data provide evidence for a "high sugar resistance" model in the mature treated leaves of the vine, since the export of carbon was reduced to ensure an elevated defence response in the treated leaf. The increase in berry sugar concentration seven days after treatment can be explained by the initial prioritisation of a greater portion of the exported carbon to storage in the roots, making it available for remobilisation to the berries once the challenge to defence had passed.
这项工作旨在了解霞多丽葡萄藤在引发防御反应后，如何在根组织、果实和防御之间优先分配近期固定的光合产物。茉莉酸（JA）及其甲酯MeJA是内源性植物激素，统称为茉莉酸盐，它们在植物防御中具有信号传导作用，因此常被用于启动植物防御系统。在这里，我们通过向霞多丽葡萄藤的成熟源叶施加外源茉莉酸盐，来阐明植物防御与生长之间碳分配的优先策略。我们的结果表明，向霞多丽叶片施加茉莉酸盐可引发对[具体对象未提及]的防御反应，但这种影响局限于茉莉酸盐处理区域。我们没有发现未处理的成熟叶片或幼嫩生长组织中存在系统性防御反应的证据。施加JA降低了处理叶片的光合速率，并降低了叶片中近期固定的碳-11的输出速率。施加JA后，更大比例的可用近期固定碳被分配到根部，这表明根部的库强增加。浆果的相对库强没有变化；然而，在JA处理七天后观察到浆果糖分增加。我们得出结论，这些数据为葡萄藤成熟处理叶片中的“高糖抗性”模型提供了证据，因为碳的输出减少以确保处理叶片中有增强的防御反应。处理七天后浆果糖分浓度的增加可以解释为，最初将更大比例的输出碳优先分配到根部储存，一旦防御挑战过去，这些碳就可重新转运到浆果中。
