3.4.2. Efficiency of multiplex RT-PCR for the detection of the threeviruses in different tissues of pear and apple plantsIn spring, dormant shoots were collected from ten pear plantsand ten apple plants grown in two fields. Shoots from each plantwere divided into two groups, of which one was stored at 4◦C andanother one was cultured in water-containing pots at room temper-ature to force the leaf growth. When leaves sprouted out, total RNAwas extracted from young leaves and dormant budwoods of thosesamples, and three viruses were detected by optimized mRT-PCR.As indicated by different band intensities, different amplificationefficiencies were obtained from young leaves and dormant barks(Fig. 5). Young leaves of both pear and apple plants consistentlygave intensive and specific bands for all three viruses. The ampli-fication efficiency of ACLSV was less affected by different tissuematerials. However, the amplification efficiency of ASGV from dor-mant barks was greatly lower than that from young leaves. In youngleaf samples, the three viruses were detected in nine out of tenapple samples, and all ten pear samples were positive for ASGVand ACLSV, and nine pear samples were positive to ASPV (Fig. 5A).In dormant bark samples of apple and pear, all were detected to bepositive to ACLSV, and only four apple samples and one pear samplewas positive to ASGV, and one apple and one pear were negative toASPV, respectively. The co-efficiency rate of ACLSV detections fromyoung leaf and dormant bark samples was up to 100%, no materits hosts. The co-efficiency rates of ASPV detections from youngleaf and dormant bark samples of pear and apple were 100% and90%, respectively, and only 40% and 10% co-efficiency rates of theASGV detection of young leaf and dormant bark of apple and pear,respectively.