Search

Root-knot nematodes (RKNs) severely affect plants growth and productivity, and several commercial biocontrol bacteria can improve plants resistance to RKNs. Pseudomonas putida Sneb821 isolate was found to induce tomatoes resistance against Meloidogyne incognita. However, the molecular functions behind induced resistance remains unclear. Long non-coding RNA (lncRNA) is considered to be a new component that regulates the molecular functions of plant immunity. We found lncRNA was involved in Sneb821-induced tomato resistance to M. incognita. Compared with tomato inoculated with M. incognita, high-throughput sequencing showed that 43 lncRNAs were upregulated, while 35 lncRNAs were downregulated in tomatoes previously inoculated with Sneb821. A regulation network of lncRNAs was constructed, and the results indicated that 12 lncRNAs were found to act as sponges of their corresponding miRNAs. By using qRT-PCR and the overexpression vector pBI121, we found the expression of lncRNA44664 correlated with miR396/GRFs (growth-regulating factors) and lncRNA48734 was correlated with miR156/SPL (squamosal promoter-binding protein-like) transcription factors. These observations provided a novel molecular model in biocontrol bacteria-induced tomato resistance to M. incognita. [ABSTRACT FROM AUTHOR]

Meloidogyne incognita and Meloidogyne graminicola are root-knot nematodes (RKNs) infecting rice (Oryza sativa L.) roots and severely decreasing yield, whose mechanisms of action remain unclear. We investigated RKN invasion and development in rice roots through RNA-seq transcriptome analysis. The results showed that 952 and 647 genes were differently expressed after 6 (invasion stage) and 18 (development stage) days post inoculation, respectively. Gene annotation showed that the differentially expressed genes were classified into diverse metabolic and stress response categories. Furthermore, phytohormone, transcription factor, redox signaling, and defense response pathways were enriched upon RKN infection. RNA-seq validation using qRT-PCR confirmed that CBL-interacting protein kinase (CIPK) genes (CIPK5, 8, 9, 11, 14, 23, 24, and 31) as well as brassinosteroid (BR)-related genes (OsBAK1, OsBRI1, D2, and D11) were altered by RKN infection. Analysis of the CIPK9 mutant and overexpressor indicated that the RKN populations were smaller in cipk9 and larger in CIPK9 OX, while more galls were produced in CIPK9 OX plant roots than the in wild-type roots. Significantly fewer numbers of second-stage infective juveniles (J2s) were observed in the plants expressing the BR biosynthesis gene D2 mutant and the BR receptor BRI1 activation-tagged mutant (bri1-D), and fewer galls were observed in bri1-D roots than in wild-type roots. The roots of plants expressing the regulator of ethylene signaling ERS1 (ethylene response sensor 1) mutant contained higher numbers of J2s and developed more galls compared with wild-type roots, suggesting that these signals function in RKN invasion or development. Our findings broaden our understanding of rice responses to RKN invasion and provide useful information for further research on RKN defense mechanisms. [ABSTRACT FROM AUTHOR]