Detection Of Acidovorax Citrulli In Melon Seed By Padlock Probe

The failure to adequately identify plant pathogens from culture-based morphological techniques has led to the development of culture-independent molecular approaches. Increasingly, diagnostic laboratories are pursuing fast routine methods that provide reliable identification, sensitive detection, and accurate quantification of plant pathogens. The most important thing that detection based on PCR is how to choose specific targets, recent years, along with the development of genomics, more opportunities will be provided for plant pathogen molecular detection.Bacterial fruit blotch (BFB) of cucurbits is caused by Acidovorax citrulli(Ac) (Schaad et al.,2008;Willems et al.,1992), is a devastating seed-borne disease. Since the first observation in commercial production fields in 1965, BFB has caused millions of dollars in losses in many cucurbit-producing regions of the world. The pathogen has been a significant threat to global cucurbit production.The yield of watermelon and melon that has become the important international competitive horticulture industry with great economical rise in China was the largest in the world. It is reported that the watermelon and melon in many provinces in China have suffered from BFB in recent years, and especially in seed-cucurbit bases, Xinjiang, Hainan and Neimenggu province, the disease caused significant economic losses for farmers.Molecular detection based on PCR assays could not detect and distinguish multiple pathogens at the same time. For this reason, molecular detection technology which could greatly improve detection efficiency is a top priority. The development of molecular probe, Microarray and Macroarray technologies provided new promise for detecting multiple pathogens at same time. Padlock probes (PLPs) are long oligonucleotides, whose ends are complementary to adjacent target sequences. Upon hybridization to the target, the two ends are brought into contact, allowing PLP circularization by ligation. PLPs provide extremely specific target recognition, which is followed by universal amplification and microarray detection. Since target recognition is separated from downstream processing, PLPs enable the development of flexible and extendable diagnostic systems, targeting diverse organisms. To adapt padlock technology for diagnose, we designed and tested PLP to target various plant pathogens (Acidovorax citrulli) at the species levels. The results showed that excellent specificity was demonstrated toward the target organisms. The demonstrated system is adaptable to a wide variety of applications ranging from pest management to environmental microbe monitor.