Mesocarp color is an important agronomic trait of Cucurbita maxima and is determined mainly by the contents and compositions of the carotenoids. The two inbred lines with significant differences in fruit flesh color were used in the study, the orange ‘312-1’ and white ‘98-2’. Changes in seven carotenoid contents and compositions in the flesh of fruit produced by inbred lines ‘312-1’ and ‘98-2’ were analyzed during fruit development. The expression of eight key carotenoid biosynthesis genes in the fruit flesh were investigated during five fruit development stage in two inbred lines. As the flesh color intensified, the orange flesh color of ‘312-1’ was determined mainly by the increased contents of lutein, β-carotene and zeaxanthin and the lack of carotenoid accumulation led to the formation of white flesh in ‘98-2’ fruit. The expression of the LCY-e and CHYb genes was significantly stronger in ‘312-1’ than in ‘98-2’, and their expression was strongly correlated with lutein and β-carotene contents during fruit development. This study provides a deep understanding of the molecular mechanism of carotenoid biosynthesis in fruit flesh and provides a basis for additional studies on the highly refined improvement of squash quality.

中果皮颜色是葫芦科植物的重要农艺性状，主要由类胡萝卜素的含量和成分决定。研究中使用了果肉颜色有显着差异的两个近交系，橙色“312-1”和白色“98-2”。分析了近交系'312-1'和'98-2'在果实发育过程中果实果肉中7种类胡萝卜素含量和成分的变化。在两个自交系的五个果实发育阶段研究了八个关键类胡萝卜素生物合成基因在果肉中的表达。随着果肉颜色的加深，'312-1'的橙色果肉颜色主要由叶黄素、β含量增加决定-胡萝卜素和玉米黄质以及类胡萝卜素积累的缺乏导致'98-2'果实形成白色果肉。所述的表达LCY-E和CHYb基因是“312-1”比在'98显著更强-2' ，和它们的表达与叶黄素和相关β果实发育过程中胡萝卜素含量。该研究深入了解了果肉中类胡萝卜素生物合成的分子机制，并为进一步研究南瓜品质的高度精细化提高提供了基础。