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Knock‐down of transcript abundance of a family of Kunitz proteinase inhibitor genes in white clover ( Trifolium repens ) reveals a redundancy and diversity of gene function
Author(s) -
Islam Afsana,
Leung Susanna,
Burgess Elisabeth P. J.,
Laing William A.,
Richardson Kim A.,
Hofmann Rainer W.,
Dijkwel Paul P.,
McManus Michael T.
Publication year - 2015
Publication title -
new phytologist
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.742
H-Index - 244
eISSN - 1469-8137
pISSN - 0028-646X
DOI - 10.1111/nph.13543
Subject(s) - biology , gene , trifolium repens , rna interference , gene expression , transcription (linguistics) , transcription factor , microbiology and biotechnology , genetics , botany , rna , linguistics , philosophy
Summary The transcriptional regulation of four phylogenetically distinct members of a family of Kunitz proteinase inhibitor ( KPI ) genes isolated from white clover ( Trifolium repens ; designated Tr‐ KPI 1 , Tr‐ KPI 2 , Tr‐ KPI 4 and Tr‐ KPI 5 ) has been investigated to determine their wider functional role. The four genes displayed differential transcription during seed germination, and in different tissues of the mature plant, and transcription was also ontogenetically regulated. Heterologous over‐expression of Tr‐ KPI 1 , Tr‐ KPI 2 , Tr‐ KPI 4 and Tr‐ KPI 5 in Nicotiana tabacum retarded larval growth of the herbivore Spodoptera litura , and an increase in the transcription of the pathogenesis‐related genes PR 1 and PR 4 was observed in the Tr‐ KPI 1 and Tr‐ KPI 4 over‐expressing lines. RNA interference (RNAi) knock‐down lines in white clover displayed significantly altered vegetative growth phenotypes with inhibition of shoot growth and a stimulation of root growth, while knock‐down of Tr‐ KPI 1 , Tr‐ KPI 2 and Tr‐ KPI 5 transcript abundance also retarded larval growth of S. litura . Examination of these RNA i lines revealed constitutive stress‐associated phenotypes as well as altered transcription of cellular signalling genes. These results reveal a functional redundancy across members of the KPI gene family. Further, the regulation of transcription of at least one member of the family, Tr‐ KPI 2 , may occupy a central role in the maintenance of a cellular homeostasis.