Host-induced post-transcriptional hairpin RNA-mediated gene silencing of vital fungal genes confers efficient resistance against Fusarium wilt in banana.
Fusarium wilt, caused by Fusarium oxysporum f. sp. cubense (Foc), is among the most destructive diseases of banana (Musa spp.). Because no credible control measures are available, development of resistant cultivars through genetic engineering is the only option. We investigated whether intron hairpin RNA (ihpRNA)-mediated expression of small interfering RNAs (siRNAs) targeted against vital fungal genes (velvet and Fusarium transcription factor 1) in transgenic banana could achieve effective resistance against Foc. Partial sequences of these two genes were assembled as ihpRNAs in suitable binary vectors (ihpRNA-VEL and ihpRNA-FTF1) and transformed into embryogenic cell suspensions of banana cv. Rasthali by Agrobacterium-mediated genetic transformation. Eleven transformed lines derived from ihpRNA-VEL and twelve lines derived from ihpRNA-FTF1 were found to be free of external and internal symptoms of Foc after 6-week-long greenhouse bioassays. The five selected transgenic lines for each construct continued to resist Foc at 8 months postinoculation. Presence of specific siRNAs derived from the two ihpRNAs in transgenic banana plants was confirmed by Northern blotting and Illumina sequencing of small RNAs derived from the transgenic banana plants. The present study represents an important effort in proving that host-induced post-transcriptional ihpRNA-mediated gene silencing of vital fungal genes can confer efficient resistance against debilitating pathogens in crop plants.
Plant Cell Culture Technology Section, Nuclear Agriculture and Biotechnology Division, Bhabha Atomic Research Centre, Mumbai, India.
Siddhesh B
SB
Ghag
Upendra K S
UK
Shekhawat
Thumballi R
TR
Ganapathi
D001483:Base Sequence; D001681:Biological Assay; D015152:Blotting, Northern; D060467:Disease Resistance / Q000235:genetics; D005670:Fusarium / Q000235:genetics* / Q000254:growth & development / Q000502:physiology; D020868:Gene Silencing; D005800:Genes, Fungal; D054884:Host-Pathogen Interactions / Q000235:genetics*; D008969:Molecular Sequence Data; D028521:Musa / Q000235:genetics* / Q000382:microbiology*; D010935:Plant Diseases / Q000235:genetics / Q000382:microbiology*; D018515:Plant Leaves / Q000382:microbiology; D030821:Plants, Genetically Modified; D034741:RNA, Small Interfering / Q000378:metabolism*; D017423:Sequence Analysis, RNA; D014158:Transcription, Genetic; D014170:Transformation, Genetic
D034741:RNA, Small Interfering
Fusarium wilt; HIGS; banana; ihpRNA; siRNA