苜蓿花叶病毒和白三叶草花叶病毒复合侵染对本氏烟中5种激素含量的影响

为探明苜蓿花叶病毒(alfalfa mosaic virus, AMV)和白三叶草花叶病毒(white clover mosaic virus, WCMV)复合侵染的协生作用致病机理，以复合接种AMV+WCMV的本氏烟为处理，分别以单独接种AMV、WCMV、磷酸盐缓冲溶液(pH 7.0, PBS)的本氏烟为对照，采用DAS-ELISA (double-antibody sandwich enzyme-linked immunosorbent assay)方法检测了接种病毒72 h的本氏烟(Nicotiana benthamiana)叶片中的病毒含量及72～720 h内水杨酸(salicylic acid, SA)、茉莉酸(jasmonic acid, JA)、独脚金内酯(strigolactones, SLs)、油菜素内酯(brassinolide, BR)、乙烯(ethylene, ETH) 含量的变化。结果表明：AMV和WCMV 接种比例为3∶1的植株720 h时的发病症状比单独接种一种病毒(AMV或WCMV)明显，主要症状表现为轻花叶、斑驳花叶、重花叶、明脉、皱缩。检测接种72 h时叶片病毒浓度发现，接种比例3∶1的植株中AMV的浓度比单独接种AMV以及AMV和WCMV接种比例为1 ? 1和1 ? 3的处理高，而WCMV的浓度略低于其单独接种WCMV处理，高于AMV和WCMV接种比例为1 ? 1和1 ? 3的处理；接种AMV和WCMV混合液后复合侵染的本氏烟叶片中SA、JA、SLs、BR、ETH含量在一定时间内与单独接种AMV、WCMV及对照之间差异显著(P < 0.05)，其中，AMV和WCMV接种比例为3∶1的混合液可在一定时间段内提高本氏烟叶片中SA (216～504 h)、SLs (216～432 h)、BR (216～504 h)、ETH (288～720 h)含量，降低JA (216～504 h)含量，其SA、SLs、BR、ETH含量分别比单独接种AMV、WCMV和健康植株(CK)提高了36.27%以上，JA含量降低了59.09%多。

Effects of alfalfa mosaic virus and white clover mosaic virus co-infection on the contents of five endogenous hormones in Nicotiana benthamiana

This study aimed to explore the synergism pathogenic mechanism of alfalfa mosaic virus (AMV) and white clover mosaic virus (WCMV) in co-infected host. To achieve this, Nicotiana benthamiana was co-inoculated with AMV+WCMV as treatment, and N. benthamiana was noculated with AMV, WCMV alone and phosphate buffer solution (pH 7.0, PBS) as controls respectively, the viral content present in the host plant leaves when different inoculated with viruses for 72 h and the content and changes of salicylic acid (SA), jasmonic acid (JA), strigolactones (SLs), brassinolide (BR), and ethylene (ETH) within 72～720 h, were detected using the double antibody sandwich enzyme-linked immunosorbent assay (DAS-ELISA) method under laboratory conditions. The results showed that the symptoms of leaves inoculated with AMV + WCMV (3???1) were more serious than those inoculated with a single virus (AMV or WCMV), the main symptoms were light mosaic, mottled mosaic, heavy mosaic, clear veins and shrinkage. The virus concentration detection results showed that the concentration of AMV virus in leaves inoculated with AMV + WCMV (3???1) was higher than that in leaves inoculated with single virus and AMV + WCMV (1???1, 1???3); the concentration of WCMV was slightly lower than that of its single infection, and higher than that of AMV + WCMV (1???1, 1???3) co-infection at 72 hours after inoculation. Simultaneously, it was found the content of SA, JA, SLs, BR, and ETH differed significantly in the Nicotiana benthamiana leaves co-infected with AMV and WCMV and those infected with AMV or WCMV alone from that in the control treatment (P < 0.05). Among the conditions treatedt, co-infection of AMV and WCMV (3 ??1) could increase the content of SA, SLs, BR, and ETH in N. benthamiana leaves, and reduce the content of JA. The content of SA, SLs, BR, and ETH in the leaves co-infected with AMV and WCMV (3???1) was higher than that in those infected with AMV or WCMV alone and in healthy plants (CK), which was an increase of more than 36.27%. The JA content in the co-infected leaves was reduced by 59.09% or more compared to those infected with AMV and WCMV alone, and healthy plants (CK) from 72 to 720 h, respectively.