Song Xiupeng, Mo Fenglian, Yan Meixin, Zhang Xiaoqiu, Zhang Baoqing, Huang Xing, Huang Dongmei, Pan Yangfei, Verma Krishan K, Li Yang-Rui
Sugarcane Research Institute, Guangxi Academy of Agricultural Sciences/Key Laboratory of Sugarcane Biotechnology and Genetic Improvement (Guangxi), Ministry of Agriculture and Rural Affairs/Guangxi Key Laboratory of Sugarcane Genetic Improvement, Nanning 530007, China.
College of Agriculture, Guangxi University, Nanning 530004, China.
Life (Basel). 2022 Aug 8;12(8):1201. doi: 10.3390/life12081201.
Pathogen infection seriously affects plant development and crop productivity, sometimes causing total crop failure. In this study, artificial stab inoculation was used to inoculate sugarcane smut. The changes in leaf gas exchange, chlorophyll fluorescence variables, and related defense enzyme activities were measured in sugarcane cultivar ROC22 after pathogen infection. The results showed that the net photosynthetic rate (Pn), stomatal conductance (gs), and transpiration rate (Tr) downregulated in the first three days after smut infection and upregulated on the fourth day; intercellular CO concentration (Ci) increased in the first three days of smut infection and reduced on the fourth day. The chlorophyll fluorescence parameters, i.e., Fo, Fm, Fv/Fm, Fs, and Fv'/Fm' decreased at the initial stage of pathogen infection but increased rapidly up to 3 days after smut infection. It can be seen that sugarcane seedlings showed a positive response to pathogen infection. The correlation coefficient relationship between Pn, gs, and Tr reached above 0.800, showing a significant correlation; Ci was positively correlated with Fv'/Fm' and ΦPSII, reaching above 0.800 and showing a significant correlation; Fo positively correlated with Fv/Fm, Fs, and ETR; Fv /Fm was positively correlated with Fv'/Fm'; Fs significantly correlated with Fv'/Fm'; and Fv'/Fm' positively correlated with ΦPSII. After inoculation with smut, the related defense enzymes, i.e., POD, SOD, PPO, and PAL, were increased and upregulated; photosynthetic parameters can be associated with an increase in enzymatic activities. The results of this study will help to further study of the response mechanism to smut in the sugarcane growing period and provide a theoretical reference for sugarcane resistance to smut breeding.
病原菌感染严重影响植物生长发育和作物产量，有时甚至导致作物绝收。本研究采用人工刺伤接种法接种甘蔗黑穗病菌。测定了病原菌感染后甘蔗品种ROC22叶片气体交换、叶绿素荧光参数及相关防御酶活性的变化。结果表明，黑穗病菌感染后的前3天，净光合速率（Pn）、气孔导度（gs）和蒸腾速率（Tr）下调，第4天上调；胞间CO₂浓度（Ci）在黑穗病菌感染的前3天升高，第4天降低。叶绿素荧光参数，即初始荧光（Fo）、最大荧光（Fm）、PSⅡ最大光化学效率（Fv/Fm）、稳态荧光（Fs）和光化学猝灭系数（Fv'/Fm'）在病原菌感染初期降低，但在黑穗病菌感染后3天迅速升高。可见，甘蔗幼苗对病原菌感染表现出积极响应。Pn、gs和Tr之间的相关系数关系达到0.800以上，呈显著相关；Ci与Fv'/Fm'和PSⅡ实际光化学效率（ΦPSII）呈正相关，达到0.800以上，呈显著相关；Fo与Fv/Fm、Fs和电子传递速率（ETR）呈正相关；Fv/Fm与Fv'/Fm'呈正相关；Fs与Fv'/Fm'呈显著相关；Fv'/Fm'与ΦPSII呈正相关。接种黑穗病菌后，相关防御酶，即过氧化物酶（POD）、超氧化物歧化酶（SOD）、多酚氧化酶（PPO）和苯丙氨酸解氨酶（PAL）活性增加且上调；光合参数可能与酶活性的增加有关。本研究结果将有助于进一步研究甘蔗生育期对黑穗病的响应机制，为甘蔗抗黑穗病育种提供理论参考。
