广东三个柑橘品种不同生育期的黄龙病菌含量动态变化研究

Dynamic variation of Candidatus Liberibacter asiaticus titer in three citrus cultivars at different growth periods in Guangdong Province

采用实时荧光定量PCR检测了广东省3个柑橘品种在不同生育期的黄龙病菌含量,探索其动态变化规律,为病害防控提供依据。结果表明,第一年,3个品种春梢期的黄龙病菌平均含量分别为3.52×10~5、4.76×10~5、1.03×10~5拷贝/g,显著低于相应夏梢期(5.50×10~5、9.48×10~5、2.50×10~5拷贝/g)和秋梢期(5.32×10~5、9.84×10~5、2.59×10~5拷贝/g);夏梢期与秋梢期含量又显著低于相应冬梢期(21.60×10~5、17.65×10~5、6.86×10~5拷贝/g)及果实成熟期(14.57×10~5、16.45×10~5、7.96×10~5拷贝/g);砂糖橘全年黄龙病菌含量与贡柑无显著差异,但均显著高于柠檬;第二年的数据与第一年类似,但砂糖橘和贡柑在多个生育期的含菌量比上年均显著升高,而柠檬所有生育期菌量均无显著变化。结果显示:柑橘病树内的黄龙病菌含量在春梢期最低,夏梢、秋梢期次之,冬梢期及果实成熟期最高;‘柠檬’相对耐病,体现为含菌量相对较低、增速较慢。

In order to provide references for synthetically preventing Huanglongbing disease,the dynamic variation of Huanglongbing pathogen was investigated in different growth periods of three citrus cultivars with real-time quantitative PCR detection method.The results showed that in the first year,average pathogen titers on the three citrus cultivars in spring shoots period were 3.52×10~5,4.76×10~5,and1.03×10~5 copy/g,respectively,significantly lower than titers in summer shoots periods（5.50×10~5,9.48×10~5,and 2.50×10~5 copy/g）and autumn shoots period（5.32×10~5,9.84×10~5 and 2.59×10~5 copy/g）.Furthermore,the pathogen titers in summer shoots and autumn shoots periods were significantly lower than titers in winner shoots period（21.60×10~5,17.65×10~5,6.86×10~5 copy/g）and fruit maturation period（14.57×10~5,16.45×10~5 and 7.96×10~5 copy/g）.Average pathogen titers in the Shatangju cultivars had no difference with titers in the Gonggan cultivars,but both were significantly higher than those in lemon.The data of the second year was similar to those of the first year,but the pathogen titers in the four growth periods of citrus Shatangju and Gonggan cultivars were significantly higher than those in the same period of the first year.The pathogen titers in all the 5 growth periods of lemon in the second year were samilar to that in the first year.The results showed that dynamic variation of Huanglongbing pathogen had a certain relationship to the different growth periods of citrus,lemon had higher disease tolerance,which mainly reflected in the lower titers and multiplication rate of the pathogen in the tree.