Potato Leafroll Virus (PLRV) and Potato Spindle Tuber Viroid (PSTVd) are pathogenes which cause cultivars degeneratation and yield reduction of potato,and spread extensively. Previous researches indicated that the spreading of PLRV by aphids redounded to the propagation of PSTVd. Therefore, it is especially important for potato cultivars to resist PLRV and PSTVd together. An effective and economic method to cultivate virus-resistant potato cultivars could be by plant genetic engineering.
In this research marker-free bivalent expression vector p3301-DR-Isir with RNAi structure of PLRV IS and di-component ribozyme specificly cleaving PSTVd RNA(-)was constructed successfully, which could be used as gene source to transform potato cultivars for high resistances to PLRV and PSTVd.