Molecular analysis of cuticle biosynthesis and deposition in developing sweet cherry fruit

雨致果裂是甜樱桃（Prunus avium L.）生产中的一个严重问题。导致水果开裂的一个主要因素是在果皮的最外层角质层（CM）形成微观裂缝（微裂缝）。微裂纹是由CM的弹塑性应变引起的，而弹塑性应变又是由于果实快速生长阶段CM沉积不足造成的。虽然微裂缝在果实开裂中的作用已经得到了很好的确定，但对甜樱桃果实中CM生物合成和沉积的分子生物学尚不清楚。本项目研究甜樱桃CM形成的分子遗传学。目的是了解为什么新的CM材料只在早期水果发育期间交付，而不是以后。具体而言，我们将1)分析发育果实中的CM沉积，2)鉴定甜樱桃果实中促成CM形成的基因，3)鉴定在果实发育早期高水平表达、成熟果实中低水平表达的CM相关基因，以及4)研究CM相关基因的生物学功能。所获得的数据对植物CM生物学的基础研究以及水果作物的育种和生产具有重要意义。此外，它们将有助于研究其他水果作物的表面病害，包括葡萄浆果的开裂或苹果和其他物种的赤褐色。

Rain-induced fruit cracking is a serious problem in sweet cherry (Prunus avium L.) production worldwide. A major factor predisposing fruit to cracking is the formation of microscopic fractures (microcracks) in the outermost layer of the fruit skin, the cuticular membrane (CM). Microcracks result from elastic and plastic strain of the CM, which in turn is caused by inadequate CM deposition during the phase of rapid fruit growth. While the role of microcracks in fruit cracking is well established, nothing is known about the molecular biology of CM biosynthesis and deposition in sweet cherry fruit. This project investigates the molecular genetics of CM formation in sweet cherry. The aim is to understand, why new CM material is only delivered during early fruit development but not later on. In detail, we will 1) analyse CM deposition in developing fruits, 2) identify genes that contribute to CM formation in sweet cherry fruits, 3) identify CM-related genes that are expressed at high levels early in fruit development and at low levels in maturing fruits, and 4) investigate the biological functions of CM-related genes. The data obtained are relevant for both the basic research of plant CM biology, and for fruit crop breeding and production. Furthermore, they will be useful in studying surface disorders in other fruit crops including cracking of grape berry or russeting in apple and other species.