The impact of xylem geometry on olive cultivar resistance to Xylella fastidiosa : An image-based study
The impact of xylem geometry on olive cultivar resistance to Xylella fastidiosa : An image-based study
复制标题
木质部几何形状对橄榄品种对木杆菌的抗性的影响：基于图像的研究
DOI：
10.1111/ppa.13674
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发表时间：
2022
期刊：
影响因子：
2.7
通讯作者：
Walker N
中科院分区：
文献类型：
--
作者：
Walker N
顶天木霉是一种木质部受限的植物病原菌，侵染全球许多作物，是最近意大利橄榄病流行的原因。建议的一种减轻损失的策略是用抗病品种重新种植敏感作物。几个遗传、生化和生物物理性状与X.Fastidiosadis抗性有关。然而，支撑耐药性的机制却知之甚少。我们推测，橄榄品种对感染的敏感性将与木质部血管直径相关，较窄的血管对空气栓塞具有抵抗力，并且具有较慢的流速限制病原体的传播。为了验证这一点，我们使用X射线计算机断层扫描技术扫描了四个橄榄品种的茎，这些品种对白纹伊蚊的敏感度不同。扫描是通过一种定制的方法进行的，这种方法将血管分割，便于直径测量。虽然不同品种间茎平均导管截面直径的比较没有显著差异，但在比较直径分布时发现了差异。此外，测量表明，尽管血管直径分布可能对Leccino的耐药性起作用，但不太可能对FS17起作用。考虑到Young-Laplace方程和Hagen-Poiseuille方程，我们推断血管系统的栓塞易感性和水力传导性的差异。我们的结果表明，易感品种，拥有更大比例的较大血管，更容易受到空气栓塞的影响。此外，结果表明，在一定的压力条件下，感病品种的功能维管系统可能会受到比抗病品种更大的胁迫。这些结果支持对木质部形态筛选的研究，以帮助指导橄榄的补种。此外，我们的框架可以测试木质部几何形状与其他作物抗病能力的相关性。
Xylella fastidiosais a xylem‐limited plant pathogen infecting many crops globally and is the cause of the recent olive disease epidemic in Italy. One strategy proposed to mitigate losses is to replant susceptible crops with resistant varieties. Several genetic, biochemical and biophysical traits are associated toX.fastidiosadisease resistance. However, mechanisms underpinning resistance are poorly understood. We hypothesize that the susceptibility of olive cultivars to infection will correlate to xylem vessel diameters, with narrower vessels being resistant to air embolisms and having slower flow rates limiting pathogen spread. To test this, we scanned stems from four olive cultivars of varying susceptibility toX.fastidiosausing X‐ray computed tomography. Scans were processed by a bespoke methodology that segmented vessels, facilitating diameter measurements. Though significant differences were not found comparing stem‐average vessel section diameters among cultivars, they were found when comparing diameter distributions. Moreover, the measurements indicated that although vessel diameter distributions may play a role regarding the resistance of Leccino, it is unlikely they do for FS17. Considering Young–Laplace and Hagen–Poiseuille equations, we inferred differences in embolism susceptibility and hydraulic conductivity of the vasculature. Our results suggest susceptible cultivars, having a greater proportion of larger vessels, are more vulnerable to air embolisms. In addition, results suggest that under certain pressure conditions, functional vasculature in susceptible cultivars could be subject to greater stresses than in resistant cultivars. These results support investigation into xylem morphological screening to help inform olive replanting. Furthermore, our framework could test the relevance of xylem geometry to disease resistance in other crops.