Expression of snakin-1 antimicrobial peptide as a strategy for HLB resistance in citrus rootstocks

GARDELLA VICTORIA; CONTI GABRIELA; JORIS GIOVANNA; HAUTEVILLE CLAUDIA; BURDYN LOURDES; GOCHEZ ALBERTO; GOMEZ CLAUDIO; ALMASIA NATALIA; NAHIRÑAK VANESA; VAZQUEZ-ROVERE CECILIA; KOBAYASH KEN; CANTEROS BLANCA; GARCÍA, M.L.; HOPP ESTEBAN; REYES CA

Riverside

Congreso; Joint Conference of the International Organization of Citrus Virologists (IOCV) and International Research Conference on Huanglongbing (IRCHLB); 2019

The disease Huanglongbing (HLB) was first detected in Argentina in Misiones Province in 2012, and currently exceed 300 positive cases including several provinces. Since 2010 there is a National HLB prevention program (http://www.senasa.gob.ar/hlb) mainly aimed to the phytosanitary control and monitoring tasks as well as diagnostic services. Among other control strategies for HLB disease, genetic engineering techniques appear as very promising. Citrus plants are mainly propagated by grafting commercial varieties onto rootstocks. The present work shows the generation of transgenic plants of one of the most common rootstocks in Argentina, Citrange troyer [(C. sinensis (L.) Osbeck x Poncirus trifoliata (L.) Raf.] using a construct for the expression of the antimicrobial peptide snakin-1 (Segura et al., 1999). This peptide was previously demonstrated to exert antimicrobial effects in potato and lettuce plants (Almasia et al., 2008; Darqui et al., 2018). We generated twelve C. troyer transgenic lines that are being rusticated in the greenhouse. Three of the lines were already characterized by molecular analysis and were positive for Snakin-1 expression by RT-PCR and Western blot. Preliminary challenge assays conducted in detached leaves against Xanthomonas sp, revealed a tolerance behavior of the transgenic lines. These lines will be then propagated and challenged against Candidatus Liberibacter. Commercial, non-GMO sweet orange scions will be grafted onto resistant/tolerant transgenic lines for field-testing to determine if the improved tolerance can also be transferred to the scion.