枇杷是江浙等地重要经济树种，但是多地因主栽品种风味偏淡、品质不佳而导致经济效益远低于预期。果实风味主要由糖酸含量决定，糖是品质形成的基础和核心，糖分配和积累水平的差异可以直接导致果实品质的巨大差距。果实糖积累水平受栽培、气候等外界条件影响，但是起决定作用的仍然是其内在因素，阐明糖积累及调控机理是实现品质调控、指导高品质育种的理论基础。近来在模式植物中发现SWEET家族基因对植物体内糖分配及生长发育起重要作用。我们前期通过对两个糖积累水平差异较大的枇杷品种不同发育时期果实转录组测序获得了枇杷SWEET基因家族12个成员，本项目在此基础上开展枇杷SWEET家族基因调控糖分配及积累机理研究，利用MALDI质谱成像、CRISPR和转录组分析技术从组织水平和分子水平寻找品种间糖积累水平差异的原因，解析糖在果实中分配、积累及调控的分子网络，从理论上探索果实品质形成机理，为育种实践提供基础。

Loquat is of economic importance around Jiang-Zhe areas, but flat flavor of leading cultivars makes the economic benefit not as good as expected. Fruit flavor mostly depends on sugar and acid contents. Among which sugar is the foundation, both of fruit taste and flavor closely connect with sugar contents, as a little difference from sugar accumulation could cause large difference in fruit quality. Sugar accumulation is affected by external conditions such as cultivation and climate, but more importantly, intrinsic conditions of cultivars are of crucial roles. Therefore, understanding the mechanism of sugar allocation and accumulation is of great importance for quality improving and for breeding as well. Recently, SWEET family has been found to have essential roles on plant sugar allocation and accumulation in model plants. Luckly, twelve members of SWEET family from loquat have been identified according to transcriptome sequencing in our previous study. This project is willing to further investigate the mechanism of SWEET family on sugar allocation and accumulation in loquat fruit. By using of MALDI imaging mass spectrometry, CRISPR and transcriptomic techniques, the different sugar accumulation mechanims between cultivars will be clarifued at histological and molecular level. The molecular network of sugar allocation, accumulation and regulation will be illustrated. The possible results of this project will provide fundamental basis for breeding.