Identification of a role for an E6-like 1 gene in early pollen-stigma interactions in Arabidopsis thaliana

Abstract

In Arabidopsis, successful pollen-stigma interactions are dependent on rapid recognition of compatible pollen by the stigmatic papillae located on the surface of the pistil and the subsequent regulation of pollen hydration and germination, and followed by the growth of pollen tubes through the stigma surface. Here we have described the function of a novel gene, E6-like 1 (E6L1), that was identified through the analysis of transcriptome datasets, as one of highestexpressed genes in the stigma, and furthermore, its expression was largely restricted to the stigma and trichomes. The first E6 gene was initially identified as a highly-expressed gene during cotton fiber development, and related E6-like predicted proteins are found throughout the Angiosperms. To date, no orthologous genes have been assigned a biological function. Both the Arabidopsis E6L1 and cotton E6 proteins are predicted to be secreted, and this was confirmed using an E6L1:RFP fusion construct. To further investigate E6L1's function, one T-DNA and two independent CRISPR-generated mutants were analyzed for compatible pollen-stigma interactions, and pollen hydration, pollen adhesion and seed set were mildly impaired for the e6l1 mutants. This work identifies E6L1 as a novel stigmatic factor that plays a role during the early post-pollination stages in Arabidopsis.

Two groups ofArabidopsisreceptor kinases preferentially regulate the growth of intraspecies pollen tubes in the female reproductive tract

“…Previously, a search for stigma-specific candidate genes failed to identify any RK genes [29, 30], and a survey of a developmental RNA-Seq transcriptome [31] for predicted A. thaliana RK genes confirmed the absence of any stigma-specific RK genes, other than the pseudogenized SRKA gene (Table S1). As many RK genes are expressed in the stigma (Table S1), we took the approach of using the stigma-specific Arabidopsis lyrata BRASSIKIN1 (Al-BKN1) pseudokinase [29] as a tool to narrow down the list of potential receptor kinase candidates to test for functions in the stigma following pollination.…”

“…All of the entry vectors created were gateway cloned into their appropriate destination vectors (pEG202, pJG4-5 or pBiFCt-2in1-CC) by using Gateway™ LR Clonase™ II Enzyme Mix (ThermoFisher Scientific). CRISPR vectors carrying two guide RNAs were cloned into pBEE401E as previously described [29, 30, 59] and transformed into A. thaliana via Agrobacterium -mediated floral dip method [60]. T1 seeds were germinated on soil and selected from spraying Basta herbicide, which was then followed with PCR screens to detect for the herbicide marker, deletions, and wild-type genes.…”

Plant proteostasis – shaping the proteome: a research community aiming to understand molecular mechanisms that control protein abundance

“…In addition to studies of plant immunity, Daphne Goring provided evidence on the role of autophagy in Brassicaceae selfincompatibility. Their findings reveal that autophagy is upregulated during pollen rejection (Doucet et al, 2019;Jany et al, 2019). In parallel, vesicle trafficking seems to be inhibited during selfincompatibility, again suggesting an interplay between vesicle transport and autophagy.…”

A System Biology Approach to Explore Host-Pathogen Interaction Under Phytochemical Cross Linkages

“…Three principle genes involved in defense responses correlated with phyto-signalling molecules were studied using Expression Angler 2016 tool with r-cut off range up to -0.23 to 0.99 (22). The data so extracted from Expression Angler 2016 tool with desired r-cut off range were subjected to yED (23) to produce co-expression networks where different colour nodes represented up-regulation and downregulation with the reference of the expressional value of principle defense gene and pathogen.…”