A simple and efficient in planta transformation method based on the active regeneration capacity of plants.

Plant genetic transformation strategies serve as essential tools for the genetic engineering and advanced molecular breeding of plants. However, the complicated operational protocols and low efficiency of current transformation strategies restrict the genetic modification of most plant species. This paper describes the development of the regenerative activity-dependent in planta injection delivery (RAPID) method based on the active regeneration capacity of plants. In this method, Agrobacterium tumefaciens is delivered to plant meristems via injection to induce transfected nascent tissues. Stable transgenic plants can be obtained by subsequent vegetative propagation of the positive nascent tissues. The method was successfully used for transformation of plants with strong regeneration capacity, including different genotypes of sweet potato (Ipomoea batatas), potato (Solanum tuberosum), and bayhops (Ipomoea pes-caprae). Compared with traditional transformation methods, RAPID has a much higher transformation efficiency and shorter duration, and it does not require tissue culture procedures. The RAPID method therefore overcomes the limitations of traditional methods to enable rapid in planta transformation and can be potentially applied to a wide range of plant species that are capable of active regeneration.

Natural allelic variation confers high resistance to sweet potato weevils in sweet potato.

Sweet potato (Ipomoea batatas L.) is a major root crop worldwide. Sweet potato weevils (SPWs) pose one of the most significant challenges to sweet potato production in tropical and subtropical regions, causing deleterious economic and environmental effects. Characterizing the mechanisms underlying natural resistance to SPWs is therefore crucial; however, the genetic basis of host SPW resistance (SPWR) remains unclear. Here we obtained two sweet potato germplasm with high SPWR and, by map-based cloning, revealed two major SPW-resistant genes-SPWR1 and SPWR2-that are important regulators of natural defence against SPWs. The SPW-induced WRKY transcriptional factor SPWR1 directly activates the expression of SPWR2, and SPWR2, the conserved dehydroquinate synthase, promotes the accumulation of quinate derivative metabolites that confer SPWR in sweet potato. Generally, our results provide new insights into the molecular mechanism underlying sweet potato-SPW interactions and will aid future efforts to achieve eco-friendly SPW management.