光质与马铃薯块茎细胞信号分子和糖苷生物碱积累的关系

马铃薯块茎糖苷生物碱(SGAs)含量如果超过20mg100g-1FW,人畜食用即可引起中毒。而马铃薯块茎中SGAs的积累受多种因素的影响,其中受温度与光照影响较大。为减少马铃薯块茎中SGAs的积累,了解SGAs在马铃薯块茎中的积累机制,研究了同一温度下不同光质对马铃薯块茎SGAs的积累的影响。结果表明红光照射后各品种SGAs平均含量比蓝光、白光、黑暗处理分别提高26.02%、55.50%和100.79%,且在α=0.01水平上差异极显著,说明不同光质对马铃薯块茎SGAs含量影响不同,红光影响最大,蓝光次之。同时,马铃薯块茎经不同光质处理后作为第二信使的G蛋白含量在红光下较蓝光、黑暗、白光下分别上升0.95%、2.01%、3.86%,钙调蛋白含量分别增加7.94%、37.41%和87.24%。由此可知,红光是SGAs积累的重要信号分子,其信号作用启动了红光受体PHYB,与第二信使G蛋白和CaM等共同参与马铃薯块茎SGAs的代谢积累。

Relation between Light Qualities and Accumulation of Steroidal Glycoalkaloids as Well as Signal Molecule in Cell in Potato Tubers

The potato steroidal glycoalkaloids (SGAs) are secondary metabolites, two major SGA in cultivated potato (Solanum tuberosum) are α-chaconine and α-solanine, and their total content in tubers should not exceed the safety limit of 20 mg 100 g~(-1) FW, otherwise it can be toxic to humans. Accumulation of SGAs in potato tubers is influenced by many factors including the key environmental factors, temperature and light. In order to reduce the content of SGAs and research the accumulation mechanism of SGAs in potato tubers, in the present study we attempted to compare the contents of SGAs, second messengers-calmodulin and the G protein in potato tubers, treated with the treatments of red light, blue light, white light and darkness under the same temperature (15 ℃). The results indicated that red light significantly (P < 0.01) increased the average content of SGAs in potato tubers, with 26.02%, 55.50%, and 100.79% higher than that treated with blue light, white light and darkness, respectively. It was confirmed that light with different wavelengths has different effects on accumulation of SGAs in potato tubers. Among factors influencing the accumulation of SGAs in potato tubers, the red light took the first place and the blue light took the second place. Meanwhile, the content of second messengers-the G protein in potato tubers treated with red light was 0.95%, 2.01%, and 3.86% higher than that treated with blue light, white light and darkness, respectively. And the content of calmodulin in potato tubers treated with red light was 7.94%, 37.41%, and 87.24% higher than that treated with blue light, white light and darkness, respectively. It was inferred that the red light is the signal molecule for SGAs accumulation, which stimulates the acceptor (PHYB) of red light and participate in accumulation of SGAs in potato tubers, together with the second messenger G protein, calmodulin, and so on.