Differential Gene and Protein Expression in Soybean at Early Stages of Incompatible Interaction with Phytophthora sojae

Soybean root and stem rot caused by Phytophthora sojae is a destructive disease worldwide. Using genetic resistance is an important and major component in the integrated pest management of this disease. To understand molecular mechanisms of root and stem rot resistance in soybeans, the gene and protein expression in hypocotyls and stems of variety Suinong 10 carrying resistance genes Rps1a and Rps2 was investigated by using mRNA differential display reverse transcription PCR and two-dimensional electrophoresis at 0, 0.5, 1, 2, and 4 h after inoculation with P. sojae race 1. The results of the comparison of gene and protein expression showed that at least eight differential fragments at the transcriptional level were related to metabolic pathway, phytoalexin, and signal transduction in defense responses. Sequence analyses indicated that these fragments represented cinnamic acid 4-hydroxylase gene, ATP b gene coding ATP synthase b subunit and ubiquitin-conjugating enzyme gene which upregulated at 0.5 h post inoculation, blue copper protein gene and UDP-N-acetyl-a-D-galactosamine gene which upregulated at 2 h post inoculation, TGA-type basic leucine zipper protein TGA1.1 gene, cyclophilin gene, and 14-3-3 protein gene which upregulated at 4 h post inoculation. Three resistance-related proteins, a-subunit and b-subunit of ATP synthase, and cytochrome P450-like protein, were upregulated at 2 h post inoculation. The results suggested that resistance-related multiple proteins and genes were expressed in the recognition between soybean and P. sojae during zoospore germination, penetration and mycelium growth of P. sojae in soybean.

An Integrated Approach to Comprehend MYMIV-Susceptibility of Blackgram Cv. T9 Possessing Allele of CYR1, the Cognate R-Gene

Blackgram, an important legume crop, faces the constraint of Mungbean yellow mosaic India virus (MYMIV)-stress resulting in severe crop penalty. MYMIV-resistant plants exhibit incompatible response via a cognate CYR1 gene-mediated interaction with virus effector molecule. In this study, we searched for the susceptible allele of the “R” gene in Cv. T9. Southern hybridization study confirmed presence of an allele in Cv. T9. However, transcripts of the CYR1 could not be detected either by RT-PCR or by Northern hybridization in Cv. T9 and also in other susceptible blackgram line. The allele was isolated, sequenced and referred as cyr1. In silico study revealed that cyr1 also encodes a CC-NBS-LRR protein like CYR1. However the CC domain of cyr1 is truncated by 128 amino acid residues indicating functional impairment with respect to the signal transduction after pathogen invasion. Comparative 3D structural modeling, hydrogen bonding and Van der Waals interaction studies revealed differences between CYR1 and cyr1. Lys519 and Thr490 present in the largest pockets of the CYR1 are the key interacting hotspots between CYR1 and MYMIV coat protein (CP). The weak Van der Waals interactions and intermolecular hydrogen bonding between cyr1 and CP confers less stability to the molecular recognition complex, unlike CYR1. Thus, the present investigation revealed Cv. T9 shows compatible interaction with MYMIV due to the truncation in the cyr1 sequence and consequent structural difference in the N-terminal of CC-domain.

Unconventional routes to developing insect-resistant crops

Concerns over widespread use of insecticides and heightened insect pest virulence under climate change continue to fuel the need for environmentally safe and sustainable control strategies. However, to develop such strategies, a better understanding of the molecular basis of plant-pest interactions is still needed. Despite decades of research investigating plant-insect interactions, few examples exist where underlying molecular mechanisms are well characterized, and even rarer are cases where this knowledge has been successfully applied to manage harmful agricultural pests. Consequently, the field appears to be static, urgently needing shifts in approaches to identify novel mechanisms by which insects colonize plants and plants avoid insect pressure. In this perspective, we outline necessary steps for advancing holistic methodologies that capture complex plant-insect molecular interactions. We highlight novel and underexploited approaches in plant-insect interaction research as essential routes to translate knowledge of underlying molecular mechanisms into durable pest control strategies, including embracing microbial partnerships, identifying what makes a plant an unsuitable host, capitalizing on tolerance of insect damage, and learning from cases where crop domestication and agronomic practices enhance pest virulence.