Institute for Horticultural Production Systems, Leibniz-University Hannover, Hannover, Germany.
Hansabred GmbH & Co. KG, Dresden, Germany.
PeerJ. 2024 Aug 29;12:e17960. doi: 10.7717/peerj.17960. eCollection 2024.
Water soaking is a commercially important disorder of field-grown strawberries that is exacerbated by surface wetness and high humidity. The objective was to establish the effect of genotype on susceptibility to water soaking. Three greenhouse-grown model 'collections' were used comprising a total of 172 different genotypes: (1) a segregating F2 population, (2) a collection of strawberry cultivars and breeding clones, and (3) a collection of wild species. A standardized immersion assay was used to induce water soaking. Potential relationships between water soaking and water uptake characteristics, depth of the achene depressions, fruit firmness, cuticle mass and strain relaxation and microcracking were investigated. Further, the effect of downregulating the polygalacturonase genes ( and ) on the susceptibility to water soaking was investigated. The collection of wild species was most susceptible to water soaking. This was followed by the collection of cultivars and breeding clones, and by the F2 population. Susceptibility to water soaking was strongly correlated with water uptake rate (mass of water, per fruit, per time). For the pooled dataset of 172 genotypes, 46% of the variability in water soaking was accounted for by the permeance of the skin to osmotic water uptake. Susceptibility to water soaking was not, or was only poorly correlated with measurements of fruit surface area or of the osmotic potential of the expressed fruit juice. The only exceptions were the wild species which were highly variable in fruit size and also in fruit osmotic potential. For genotypes from the F2 and the wild species collections, firmer fruit were less susceptible to water soaking than softer fruit. There were no relationships between fruit firmness and susceptibility to water soaking in transgenic plants in which and were down-regulated. Susceptibility to water soaking was not related to cuticle mass per unit fruit surface area, nor to strain relaxation of the cuticle upon isolation, nor to achene position. In summary, strawberry's susceptibility to water soaking has a significant genetic component and is closely and consistently related to the skin's permeance to osmotic water uptake.
水渍病是一种商业化的草莓田间重要病害，在表面湿润和高湿度的情况下会加剧。本研究的目的是确定基因型对水渍病易感性的影响。使用了三个温室生长的模型“集合”，共包含 172 个不同的基因型：（1）一个分离的 F2 群体，（2）草莓品种和育种克隆的集合，（3）野生种的集合。使用标准化的浸泡测定法来诱导水渍病。研究了水渍病与水分吸收特性、种脐凹陷深度、果实硬度、角质层质量和应变松弛与微裂纹之间的潜在关系。此外，还研究了下调多聚半乳糖醛酸酶基因（和）对水渍病易感性的影响。野生种集合最易感染水渍病。其次是品种和育种克隆的集合，然后是 F2 群体。水渍病的易感性与水分吸收速率（单位果实的水分质量，单位时间）呈强相关。对于 172 个基因型的汇总数据集，皮肤对渗透水分吸收的渗透率解释了水渍病的 46%的可变性。水渍病的易感性与果实表面积或表达果实汁液的渗透压的测量值没有相关性，或者相关性很差。唯一的例外是野生种，它们在果实大小和果实渗透压方面具有高度的可变性。对于 F2 和野生种集合的基因型，硬度较高的果实比硬度较低的果实对水渍病的敏感性低。在下调和的转基因植物中，果实硬度与水渍病易感性之间没有关系。水渍病的易感性与单位果实表面面积的角质层质量无关，也与角质层隔离时的应变松弛无关，也与种脐位置无关。综上所述，草莓对水渍病的易感性具有显著的遗传成分，与皮肤对渗透水分吸收的渗透率密切且一致相关。
