Project description:We report the transcriptional response to Colorado potato beetle herbivory in leaves of the highly beetle resistant Solanum chacoense diploid line USDA8380-1 (80-) and a susceptible F2 individual (EE501F2_093) derived from a cross between 80-1 and a beetle susceptible line S. chacoense M6. Sampling tissue in a time course during adult Colorado potato beetle feeding provides novel insight to the transcriptomic defense response to this important pest.
Project description:Purpose: MicroRNAs (miRNAs) are ubiquitous components of endogenous plant transcriptome. miRNAs are small, single-stranded and ~21 nt long RNAs which regulate gene expression at the post-transcriptional level and are known to play essential roles in various aspects of plant development and growth. Previously, a number of miRNAs have been identified in potato through in silico analysis and deep sequencing approach. However, identification of miRNAs through deep sequencing approach was limited to a few tissue types and developmental stages. This study reports the identification and characterization of potato miRNAs in three different vegetative tissues and four stages of tuber development by high throughput sequencing. Results: Small RNA libraries were constructed from leaf, stem, root and four early developmental stages of tuberization and subjected to deep sequencing, followed by bioinformatics analysis. A total of 89 conserved miRNAs (belonging to 33 families), 147 potato-specific miRNAs (with star sequence) and 112 candidate potato-specific miRNAs (without star sequence) were identified. The digital expression profiling based on TPM (Transcripts Per Million) and qRT-PCR analysis of conserved and potato-specific miRNAs revealed that some of the miRNAs showed tissue specific expression (leaf, stem and root) while a few demonstrated tuberization stage-specific expressions. Targets were predicted for identified conserved and potato-specific miRNAs, and predicted targets of four conserved miRNAs, miR160, miR164, miR172 and miR171, which are ARF16 (Auxin Response Factor 16), NAM (NO APICAL MERISTEM), RAP1 (Relative to APETALA2 1) and HAIRY MERISTEM (HAM) respectively, were experimentally validated using 5′RLM-RACE (RNA ligase mediated rapid amplification of cDNA ends). Gene ontology (GO) analysis for potato-specific miRNAs was also performed to predict their potential biological functions. Conclusions: We report a comprehensive study of potato miRNAs at genome-wide level by high-throughput sequencing and demonstrate that these miRNAs have tissue and/or developmental stage specific expression profile. Also, predicted targets of conserved miRNAs were experimentally confirmed for the first time in potato. Our findings indicate the existence of extensive and complex small RNA population in this crop and suggest their important role in pathways involved in diverse biological processes, including tuber developmental process.
Project description:Self-incompatibility (SI) is a genetic mechanism that allows flowering plants to identify and block fertilization by self-pollen. In the Solanaceae, SI is controlled by a multiallelic S-locus encoding both S-RNases and F-box proteins as female and male determinants, respectively. S-RNase activity is essential for pollen rejection, and a minimum threshold value of S-RNases in the style is also required. Here we present biochemical evidence that eEF1A is a novel S-RNase-binding partner in vitro. We further show that the normal actin binding activity of eEF1A is enhanced by the presence of S-RNase. Lastly, we find that there is a co-localization of S-RNase and actin in the incompatible pollen tubes in structures reminiscent of the actin bundles formed by eEF1A. We propose that increased binding of eEF1A to actin in the presence of S-RNase could help explain the disruption of the actin cytoskeleton observed during SI reactions.
Project description:Glycoalkaloids are Solanum bioactive compounds and are involved in allelopathic interactions. To achieve a better understanding of plant–plant interactions, it is essential to deeply examine the trait distribution in a segregating population. In the present paper, we used transcriptomic and metabolomic approaches to recognize the phytotoxic abilities of potato plants originating from a diploid segregating F1 population with particular emphasis on glycoalkaloids in potato groups characterized by a high glycoalkaloid content. In potato F1 individuals, six glycoalkaloids were recognized: solasonine, solamargine, α-solanine, α-chaconine, leptinine I, and leptine II. In the bulk samples characterized by a high total glycoalkaloid content and various phytotoxic potential, high - A’, low - B’ and hormesis - F’, a significant role of the glycoalkaloid composition in the expression of phytotoxic potential was revealed. In particular, leptine II, solasonine and solamargine were present. Based on the RNA-seq analysis of the bulk samples, a flavonol synthase/flavanone 3-hydroxylase-like gene responsible for flavonoid synthesis was upregulated in comparison A’ vs. B’ and A’ vs. F’ (Log2FC=8.30 and 6.40, respectively). The population-level evaluation of phytotoxic potential confirmed a significant negative correlation between total glycoalkaloid content and phytotoxic potential (r=-0.211) but only after correction for total flavonoid content.