Wang Shu-Bin, Tian Shi-Lin, Shah Syed N M, Pan Bao-Gui, Diao Wei-Ping, Gong Zhen-Hui
Institute of Vegetable Crops, Jiangsu Academy of Agricultural Sciences Nanjing, China.
College of Horticulture, Northwest A&F University Yangling, China ; Department of Bioengineering, Huanghuai University Zhumadian, China.
Front Plant Sci. 2015 Oct 13;6:850. doi: 10.3389/fpls.2015.00850. eCollection 2015.
Light is an important environmental factor for fruit development and ripening in pepper plant. Fruit bagging is a significant agrotechnology practiced for the illumination regulation of fruits; some previous researches have shown that fruit bagging could improve the appearance and external quality of fruits and cause them to mature early. However, it would decrease the intrinsic qualities of fruits; especially, fruit bagging could decrease the content of capsanthin in peppers. On the basis of these details, fruit bagging was used as the method of fruit shade stress in this study to explore the characteristics and molecular mechanisms of pepper fruit's color change under shade stress. By using cDNA-AFLP under fruit shading, a fragment related to fruit color was obtained. Next, the full-length coding sequence of the gene was cloned from the pepper fruits. Homologous gene alignment confirmed that the gene has high homology with the rbcL gene, named CarbcL. The function of the CarbcL gene was identified through virus-induced gene silencing (VIGS); it was found that the fruit color changed completely from green to red except for some residue of green fleck when CarbcL gene was silenced, and the green color of fruits had not fully faded in the control group and the empty vector group. The combine determination of chlorophyll content showed that CarbcL was involved in the metabolic control of chlorophyll in pepper fruits; subsequently, HPLC was used to determine the content of capsanthin in pepper fruit which the CarbcL gene was silencing, and it was also found that the content of capsanthin decreased appreciably. These results further confirmed that CarbcL gene was involved in the adjustment of chlorophyll and capsanthin.
光是辣椒植株果实发育和成熟的重要环境因素。果实套袋是一项用于调节果实光照的重要农业技术；先前的一些研究表明，果实套袋可以改善果实的外观和外在品质，并使其早熟。然而，这会降低果实的内在品质；尤其是，果实套袋会降低辣椒中辣椒红素的含量。基于这些细节，本研究采用果实套袋作为果实遮荫胁迫的方法，以探究遮荫胁迫下辣椒果实颜色变化的特征和分子机制。通过在果实遮荫条件下使用cDNA-AFLP，获得了一个与果实颜色相关的片段。接下来，从辣椒果实中克隆了该基因的全长编码序列。同源基因比对证实该基因与rbcL基因具有高度同源性，命名为CarbcL。通过病毒诱导基因沉默（VIGS）鉴定了CarbcL基因的功能；结果发现，当CarbcL基因沉默时，果实颜色除了有一些绿色斑点残留外，完全从绿色变为红色，而对照组和空载体组果实的绿色并未完全褪去。叶绿素含量的联合测定表明，CarbcL参与了辣椒果实中叶绿素的代谢调控；随后，使用高效液相色谱法测定了CarbcL基因沉默的辣椒果实中辣椒红素的含量，还发现辣椒红素的含量明显降低。这些结果进一步证实，CarbcL基因参与了叶绿素和辣椒红素的调节。
