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Developing SCAR Markers And FQ-PCR To Study Predation On Bemisia Tabaci

Posted on:2006-09-07Degree:MasterType:Thesis
Country:ChinaCandidate:Z C LvFull Text:PDF
GTID:2133360152494252Subject:Agricultural Entomology and Pest Control
Abstract/Summary:PDF Full Text Request
B-biotype of Bemisia tabaci (Gennadius) is a major insect pest in greenhouse crops and field crops. In both South and North China, it has caused serious damages to cottons, vegetables and ornamentals since the 90s' of last century. Environmental friendship measures for Bemisia control are deadly needed. In the present study, the relationships between B. tabaci and predators were evaluated by using SCAR markers and FQ-PCR. The results are as follows:1. The SCAR markers were firstly used for qualitative evaluating the relationships between predators and B. tabaci in China.1.1. The detection-system of SCAR markers were set up for evaluating the predation on B. tabaci . DNA markers of B. tabaci were developed to detect remains of the whitefly in the gut of the predator Propylaea japonica (Thunberg). A 347bp DNA fragment of B. tabaci, absent in other closely related prey species and in the predator banding pattern, was identified by RAPD analysis. After cloning and sequencing this fragment, one pair of SCAR primers was developed, amplified single band of 234bp. Specificity tests performed with this pair of primers showed the presence of the 234bp band for B. tabaci in all stages.1.2. The major B. tabaci predators in cotton fields were indicated. The results showed that P. japonica larva, Harmonia axyridis (Pallas) larva, Orius sauteri (Zheng), Chrysopa and spider are the important predators preying on B. tabaci in cotton fields.2. FQ-PCR was used in studying the relationships evaluation between predators andprey.2.1 The calibration curve for the quantifying analyses of B. tabaci DNA fragment was set up, and the conditions and system compositions of real-time detection were optimized. The sensitivity of TaqMan probe was also determined.2.2 The relationships between diet size and digesting duration and predatory quantity analyses were real-time detected by TaqMan reaction. The relationships between diet size and quantity analysis were evaluated the formula Y = 0.0718X + 3.5058 (R2 = 0.9701), and between digesting duration and quantity analysis were Y = -0.0061X + 3.2016 (R2= 0.8784).2.3 Real-time detection for predators collected in cotton fields showed that P. japonica larva was the most powerful predator of B. tabaci, then followed by H. axyridis larva and spider, and O. sauteri and Chrysopa.The present study indicated that the SCAR primers for B. tabaci could be used to set up predatory tree of the whitefly in different crop fields and districts. The combination of the SCAR markers and real-time detection could be used to quantity analysis the predation on preys in field study.
Keywords/Search Tags:Bemisia tabaci, Predators, SCAR markers, FQ-PCR, Taqman probe, Real-time detection
PDF Full Text Request
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