DICER-like proteins and their role in plant-herbivore interactions in Nicotiana attenuata.
DICER-like (DCL) proteins produce small RNAs that silence genes involved in development and defenses against viruses and pathogens. Which DCLs participate in plant-herbivore interactions remains unstudied. We identified and stably silenced four distinct DCL genes by RNAi in Nicotiana attenuata (Torrey ex. Watson), a model for the study of plant-herbivore interactions. Silencing DCL1 expression was lethal. Manduca sexta larvae performed significantly better on ir-dcl3 and ir-dcl4 plants, but not on ir-dcl2 plants compared to wild type plants. Phytohormones, defense metabolites and microarray analyses revealed that when DCL3 and DCL4 were silenced separately, herbivore resistance traits were regulated in distinctly different ways. Crossing of the lines revealed complex interactions in the patterns of regulation. Single ir-dcl4 and double ir-dcl2 ir-dcl3 plants were impaired in JA accumulation, while JA-Ile was increased in ir-dcl3 plants. Ir-dcl3 and ir-dcl4 plants were impaired in nicotine accumulation; silencing DCL2 in combination with either DCL3 or DCL4 restored nicotine levels to those of WT. Trypsin proteinase inhibitor activity and transcripts were only silenced in ir-dcl3 plants. We conclude that DCL2/3/4 interact in a complex manner to regulate anti-herbivore defenses and that these interactions significantly complicate the already challenging task of understanding smRNA function in the regulation of biotic interactions.
Department of Molecular Ecology, Max Planck Institute for Chemical Ecology, 07745 Jena, Germany.
Tohir Ahmadovich
TA
Bozorov
Shree Prakash
SP
Pandey
Son Truong
ST
Dinh
Sang-Gyu
SG
Kim
Maria
M
Heinrich
Klaus
K
Gase
Ian T
IT
Baldwin
D000818:Animals; D018506:Gene Expression Regulation, Plant / Q000187:drug effects; D020868:Gene Silencing / Q000187:drug effects; D017343:Genes, Plant / Q000235:genetics; D060434:Herbivory / Q000187:drug effects / Q000502:physiology*; D006790:Host-Parasite Interactions / Q000187:drug effects / Q000502:physiology*; D007814:Larva / Q000187:drug effects / Q000502:physiology; D018402:Manduca / Q000187:drug effects / Q000502:physiology; D009154:Mutation / Q000235:genetics; D020411:Oligonucleotide Array Sequence Analysis; D010641:Phenotype; D010937:Plant Growth Regulators / Q000494:pharmacology; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism*; D043244:Ribonuclease III / Q000235:genetics / Q000378:metabolism; D014026:Nicotiana / Q000187:drug effects / Q000235:genetics / Q000378:metabolism* / Q000469:parasitology*; D014158:Transcription, Genetic / Q000187:drug effects; D014361:Trypsin Inhibitors / Q000378:metabolism
D010937:Plant Growth Regulators; D010940:Plant Proteins; D014361:Trypsin Inhibitors; D043244:Ribonuclease III