Construction of cDNA Expression Library of Watermelon and Screening and Identification of Interaction Partner of FonSIX6,a Virulence Factor from Fusarium oxysporum f. sp. niveurn Construction of cDNA Expression Library of Watermelon and Screening and Identification of Interaction Partner of FonSIX6,a Virulence Factor from Fusarium oxysporum f. sp. niveurn XopXccP, a putative type III effector gene of Xanthomonas campestris pv. campestris, is required for pathogenicity on host plants