van den Berg F, Paveley N D, Bingham I J, van den Bosch F
First author: Agriculture and Horticulture Department, Fera Science Ltd., Sand Hutton, York, YO41 1LZ, United Kingdom; second author: Plant Pathology Department, ADAS, High Mowthorpe, Duggleby, Malton, North Yorkshire, YO17 8BP, United Kingdom; third author: Crop & Soils Systems, Scotland's Rural College, Kings Buildings, West Mains Road, Edinburgh EH9 3JG, United Kingdom; and fourth author: Computational and Systems Biology, Rothamsted Research, Harpenden, Hertfordshire, AL5 2JQ, United Kingdom.
Phytopathology. 2017 Dec;107(12):1468-1478. doi: 10.1094/PHYTO-07-16-0283-R. Epub 2017 Oct 10.
Tolerance is defined as the ability of one cultivar to yield more than another cultivar under similar disease severity. If both cultivars suffer an equal loss in healthy (green) leaf area duration (HAD) over the grain filling period due to disease presence, then the yield loss per unit HAD loss is smaller for a more tolerant cultivar. Little is understood of what physiological and developmental traits of cultivars determine disease tolerance. In this study, we use a mathematical model of wheat to investigate the effect of a wide range of wheat phenotypes on tolerance. During the phase from stem extension to anthesis, the model calculates the assimilate source and sink potential, allowing for dynamic changes to the source-sink balance by partitioning assimilates between ear development and storage of water-soluble carbon (WSC) reserves, according to assimilate availability. To quantify tolerance, rates of epidemic progress were varied on each phenotype, leading to different levels of HAD loss during the postanthesis, grain-filling period. Model outputs show that the main determinant of tolerance is the total amount of assimilate produced per grain during the rapid grain-fill period, leading to a strong positive correlation between HAD per grain and tolerance. Reductions in traits that affect carbon assimilation rate and increases in traits that determine the amount of structural biomass in the plant increase disease tolerance through their associated reduction in number of grains per ear. Some of the most influential traits are the canopy green area index, carbon use efficiency, and leaf specific weight. Increased WSC accumulation can either increase or decrease tolerance. Furthermore, a cultivar is shown to be maximally tolerant when a crop is able to just fill its total sink size in the presence of disease. The model has identified influential functional traits and established that their associations with tolerance have a mechanistic basis.
耐受性被定义为一个品种在相似病害严重程度下比另一个品种产量更高的能力。如果两个品种在灌浆期由于病害导致健康（绿色）叶面积持续时间（HAD）的损失相等，那么对于耐受性更强的品种，单位HAD损失的产量损失更小。对于品种的哪些生理和发育性状决定病害耐受性，人们了解甚少。在本研究中，我们使用一个小麦数学模型来研究广泛的小麦表型对耐受性的影响。在茎伸长到开花阶段，该模型计算同化物的源和库潜力，根据同化物的可利用性，通过在穗发育和水溶性碳（WSC）储备储存之间分配同化物，允许源 - 库平衡的动态变化。为了量化耐受性，在每个表型上改变病害流行进展速率，导致花后灌浆期不同水平的HAD损失。模型输出表明，耐受性的主要决定因素是快速灌浆期每粒产生的同化物总量，导致每粒HAD与耐受性之间存在强正相关。影响碳同化率的性状减少以及决定植物结构生物量的性状增加，通过它们相关的每穗粒数减少来提高病害耐受性。一些最有影响力的性状是冠层绿色面积指数、碳利用效率和叶比重量。WSC积累增加可能会增加或降低耐受性。此外，当作物在有病害的情况下能够刚好填满其总库大小时，一个品种表现出最大耐受性。该模型已经确定了有影响力的功能性状，并确定它们与耐受性的关联有一个机制基础。
