Laboratory of Hormonal Control of Plant Development, Departamento de Ciências Biológicas, Escola Superior de Agricultura "Luiz de Queiroz", Universidade de São Paulo, CP 09, 13418-900, Piracicaba, SP, Brazil.
Departamento de Biologia Vegetal, Universidade Federal de Viçosa, CEP 36570-900, Viçosa, MG, Brazil.
J Plant Physiol. 2021 May;260:153413. doi: 10.1016/j.jplph.2021.153413. Epub 2021 Apr 6.
Trichomes are epidermal structures with a large variety of ecological functions and economic applications. Glandular trichomes produce a rich repertoire of secondary metabolites, whereas non-glandular trichomes create a physical barrier on the epidermis: both operate in tandem against biotic and abiotic stressors. A deeper understanding of trichome development and function would enable the breeding of more resilient crops. However, little is known about the impact of altered trichome density on leaf photosynthesis, gas exchange and energy balance. Previous work has compared multiple, closely related species differing in trichome density. Here, we analysed monogenic trichome mutants in the same tomato genetic background (Solanum lycopersicum cv. 'Micro-Tom'). We determined growth parameters, leaf spectral properties, gas exchange and leaf temperature in the hairs absent (h), Lanata (Ln) and Woolly (Wo) trichome mutants. Shoot dry weight, leaf area, leaf spectral properties and cuticular conductance were not affected by the mutations. However, the Ln mutant showed increased net carbon assimilation rate (A), associated with higher stomatal conductance (g), with no differences in stomatal density or stomatal index between genotypes. Leaf temperature was furthermore reduced in Ln in the hottest, early hours of the afternoon. We show that a single monogenic mutation that modifies trichome density, a desirable trait for crop breeding, concomitantly improves leaf gas exchange and reduces leaf temperature.
表皮毛是具有多种生态功能和经济应用的表皮结构。腺毛产生丰富的次生代谢产物，而非腺毛在表皮上形成物理屏障：两者协同作用以抵御生物和非生物胁迫。深入了解表皮毛的发育和功能将使培育更具弹性的作物成为可能。然而，人们对改变表皮毛密度对叶片光合作用、气体交换和能量平衡的影响知之甚少。以前的工作比较了多种密切相关的物种，这些物种在表皮毛密度上存在差异。在这里，我们在相同的番茄遗传背景（Solanum lycopersicum cv. 'Micro-Tom'）中分析了单基因表皮毛突变体。我们确定了无毛（h）、Lanata（Ln）和Woolly（Wo）表皮毛突变体的生长参数、叶片光谱特性、气体交换和叶片温度。突变对茎干重、叶面积、叶片光谱特性和角质层导度没有影响。然而，Ln 突变体表现出净碳同化率（A）的增加，与较高的气孔导度（g）相关，而不同基因型之间的气孔密度或气孔指数没有差异。此外，Ln 突变体的叶片温度在下午最热的早期也降低了。我们表明，单一的单基因突变改变了表皮毛密度，这是作物育种的理想特征，同时改善了叶片气体交换并降低了叶片温度。
