Overexpression of AtSHN1/WIN1 Provokes Unique Defense Responses

Abstract

The plant cell cuticle serves as the first barrier protecting plants from mechanical injury and invading pathogens. The cuticle can be breached by cutinase-producing pathogens and the degradation products may activate pathogenesis signals in the invading pathogens. Cuticle degradation products may also trigger the plant’s defense responses. Botrytis cinerea is an important plant pathogen, capable of attacking and causing disease in a wide range of plant species. Arabidopsis thaliana shn1-1D is a gain-of-function mutant, which has a modified cuticular lipid composition. We used this mutant to examine the effect of altering the whole-cuticle metabolic pathway on plant responses to B. cinerea attack. Following infection with B. cinerea, the shn1-1D mutant discolored more quickly, accumulated more H2O2, and showed accelerated cell death relative to wild-type (WT) plants. Whole transcriptome analysis of B. cinerea-inoculated shn1-1D vs. WT plants revealed marked upregulation of genes associated with senescence, oxidative stress and defense responses on the one hand, and genes involved in the magnitude of defense-response control on the other. We propose that altered cutin monomer content and composition of shn1-1D plants triggers excessive reactive oxygen species accumulation and release which leads to a strong, unique and uncontrollable defense response, resulting in plant sensitivity and death.

The suppression of AtPrx52 affects fibers but not xylem lignification in Arabidopsis by altering the proportion of syringyl units

“…This protein is annotated as a basic peroxidase (theoretical pI 8.85) and has been described as one of the closest homolog to ZePrx (Herrero et al ). This protein is expressed in healthy, non‐stressed plants, but its expression is also induced under fungi, bacteria and insect attack (Little et al , Mohr and Cahill , Floerl et al , Sela et al ).…”

“…AtPrx52 has been reported to be expressed in roots (Méndez‐Bravo et al ), shoots (Méndez‐Bravo et al ), leaves (Little et al , Floerl et al , Sela et al ) and stamen (Cai and Lashbrook ). However, despite its close homology to ZePrx, which is highly expressed in hypocotyls and epicotyls, no bibliographic data are available concerning the expression of AtPrx52 in Arabidopsis stems.…”

CYCLIN-DEPENDENT KINASE8 Differentially Regulates Plant Immunity to Fungal Pathogens through Kinase-Dependent and -Independent Functions in Arabidopsis

“…It was previously reported that overexpression of the TF WIN1 increases cuticle thickness (Broun et al, 2004;Kannangara et al, 2007) and results in susceptibility to B. cinerea (Sela et al, 2013), which contrasts with the phenotypes of the cdk8 mutant. These observations suggest that CDK8 and WIN1 have overlapping functions.…”

“…LACS2 encodes a member of the long-chain acyl-CoA synthases involved in cutin biosynthesis in Arabidopsis (Schnurr et al, 2004). Interestingly, WIN1 overexpression results in increased expression of several wax biosynthesis genes, increased alkane levels, and susceptibility to fungal infection (Broun et al, 2004;Sela et al, 2013). Due to the lack of appropriate loss-of-function alleles of the WIN1 gene, we could not make direct comparisons of the win1 and cdk8 mutants.…”

Arabidopsis HSP70‐16 is required for flower opening under normal or mild heat stress temperatures

“…Plant cuticle is also vital for plant growth and development; it prevents or promotes postgenital organ fusion and mediates interactions between pollens and pistils (Lolle, Hsu, & Pruitt, 1998). Previous studies have shown that disruption of cuticle formation or patterning in plants affects not only vegetative and reproductive development but also responses to biotic or abiotic stresses (Aharoni et al, 2004;Kurdyukov et al, 2006;Lolle et al, 1998;Panikashvili et al, 2007Panikashvili et al, , 2010Sela et al, 2013;Shi et al, 2011Shi et al, , 2013Sieber et al, 2000;Smirnova et al, 2013). Among them, defective-cuticle-induced postgenital fusion between vegetative and reproductive organs or between floral organs often results in defective growth and development and abnormal stress response.…”