Leaf proteome reveals the alterations in photosynthesis and defense-related proteins between potato tetraploid cultivars and diploid wild species

Transcriptome analysis of genes involved in the pathogenesis mechanism of potato virus Y in potato cultivar YouJin

Introduction

Potatoes (Solanum tuberosum L.) can be infected by various viruses, but out of all of viruses, the potato virus Y (PVY) is the most detrimental. Research shows that the potato cultivar YouJin is especially vulnerable to PVY and displays severe symptoms, including leaf vein chlorosis, curled leaf margins, large necrotic spots on the leaf blades, and the growth of small new leaves.

Methods

PVY infection in potato cultivar YouJin was confirmed through symptom observation, RT-PCR, and Western blot analysis. Transcriptome sequencing was used to analyze the genes associated with PVY pathogenesis in this cultivar.

Result

Transcriptome analysis of differential genes was conducted in this study to examine the pathogenesis of PVY on YouJin. The results showed that 1,949 genes were differentially regulated, including 853 upregulated genes and 1,096 downregulated genes. The Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analysis indicated that carbohydrate synthesis and metabolism pathways were suppressed, and electron transferase and hydrolase activities were reduced. Moreover, there were increased expression levels of protein kinase genes. By focusing on plant-pathogen interaction pathways, six core genes all upregulating the WARK family of transcription factors were obtained. Additionally, a constructed PPI network revealed the identification of key modular differential genes, such as downregulated photosynthesis-related protein genes and upregulated AP2/ERF-ERF transcription factors. Functional network enrichment analysis revealed that PVY infection limited RNA metabolism, glutathionylation, and peroxiredoxin activity while triggering the expression of associated defense genes in YouJin. After analyzing the above, 26 DEGs were screened and 12 DEGs were confirmed via RT-qPCR.

Conclusion

These results establish a hypothetical framework for clarifying the pathogenesis of PVY in the YouJin variety of potatoes, which will help design the disease resistance of YouJin.

Overexpression of BnMYBL2-1 improves plant drought tolerance via the ABA-dependent pathway

Drought stress is a major environmental challenge that poses considerable threats to crop survival and growth. Previous research has indicated anthocyanins play a crucial role in alleviating oxidative damage, photoprotection, membrane stabilization, and water retention under drought stress. However, the presence of MYBL2 (MYELOBBLASTOSIS LIKE 2), an R3-MYB transcription factor (TF) which known to suppress anthocyanin biosynthesis. In this study, four BnMYBL2 members were cloned from Brassica napus L, and BnMYBL2-1 was overexpressed in Triticum aestivum L (No BnMYBL2 homologous gene was detected in wheat). Subsequently, the transgenic wheat lines were treated with drought, ABA and anthocyanin. Results showed that transgenic lines exhibited greater drought tolerance compared to the wild-type (WT), characterized by improved leaf water content (LWC), elevated levels of soluble sugars and chlorophyll, and increased antioxidant enzyme activity. Notably, transgenic lines also exhibited significant upregulation in abscisic acid (ABA) content, along with the transcriptional levels of key enzymes involved in ABA signalling under drought. Results also demonstrated that BnMYBL2-1 promoted the accumulation of ABA and anthocyanins in wheat. Overall, the study highlights the positive role of BnMYBL2-1 in enhancing crop drought tolerance through ABA signalling and establishes its close association with anthocyanin biosynthesis. These findings offer valuable insights for the development of drought-resistant crop varieties and enhance the understanding of the molecular mechanisms underlying plant responses to drought stress.

A Comparative Study of Morphology, Photosynthetic Physiology, and Proteome between Diploid and Tetraploid Watermelon (Citrullus lanatus L.)

Watermelon is an important fruit that is widely distributed around the world. In particular, the production and consumption of watermelon in China ranks first in the world. Watermelon production is severely affected by a variety of biotic and abiotic stresses during cultivation, and polyploidization can promote stress resistance and yield. However, the morphological and physiological characteristics of tetraploid watermelon and the underlying molecular mechanisms are still poorly understood. In this study, we revealed that the leaves, fruits, and seeds of tetraploid watermelon were significantly larger than those of the diploid genotype. Some physiological characteristics, including photosynthetic rate (Pn) and stomatal conductance (Gs), were greater, whereas the intercellular CO₂ concentration (Ci) and transpiration rate (Tr) were lower in tetraploid than in diploid watermelon. Two-dimensional gel electrophoresis combined with tandem mass spectrometry (MALDI-TOF/TOF) was performed to compare proteomic changes between tetraploid and diploid watermelon. A total of 21 differentially expressed proteins were identified; excluding the identical proteins, 8 proteins remained. Among them, four proteins were upregulated and four were downregulated in tetraploid versus diploid genotypes. qRT-PCR results showed inconsistencies in gene expression and protein accumulation, indicating a low correlation between gene expression and protein abundance. Generally, this study extends our understanding of the traits and molecular mechanisms of tetraploid watermelon and provides a theoretical basis for watermelon polyploid breeding.