AtAREB1 overexpression in cotton enhances water use efficiency but not improve growth in response to mild drought.

Plants have evolved complex mechanisms to cope efficiently with drought. Abscisic acid (ABA)-responsive element binding (AREB) proteins are a family of ABA-dependent transcription factors that control the expression of stress-induced genes to improve drought tolerance. It has been hypothesized that overexpression of AREB1 constitutively active is able to increase plantwater deficit resistance

AtAREB1 overexpression in cotton enhances water use efficiency but not improve growth in response to mild drought.

Plants have evolved complex mechanisms to cope efficiently with drought. Abscisic acid (ABA)-responsive element binding (AREB) proteins are a family of ABA-dependent transcription factors that control the expression of stress-induced genes to improve drought tolerance. It has been hypothesized that overexpression of AREB1 constitutively active is able to increase plantwater deficit resistance

Proteomic insights of Cowpea response to combined biotic and abiotic stresses.

Na publicação: Maria Fatima Grossi-de-Sá; Angela Mehta

In planta RNAi targeting Meloidogyne incognita Minc16803 gene perturbs nematode parasitism and reduces plant susceptibility.

Meloidogyne incognita is one of the most important plant-parasitic nematodes (PPNs) causing severe crop losses worldwide. Plants have evolved complex defense mechanisms to respond to PPNs attacks. Conversely, PPNs have evolved infection mechanisms that involve the secretion of effector proteins into host plants to suppress immune responses and facilitate para- sitism. Therefore, effector genes are attractive targets for the genetic improvement of plant resistance to M. incognita. In this study, we functionally characterized the Minc16803 (Minc3s00746g16803) putative effector gene to evaluate its role during plant-nematode interactions. First, we found that the Minc16803 gene is expressed in all nematode life stages and encodes a protein with an N-terminal signal peptide for secretion, a motif characteristic of effector proteins and with the absence of transmembrane domain. In addition, our data demonstrated that transgenic Arabidopsis thaliana lines overexpressing a Minc16803-dsRNA efficiently downregulated the Minc16803 transcripts in infecting nematodes. Furthermore, transgenic lines were significantly less susceptible to M. incognita compared to wild-type control plants. The number of galls per plant was reduced by up to 84%, while the number of egg masses per plant decreased by up to 93.3%. Moreover, galls and feed- ing sites in the roots of transgenic lines were smaller than those in the control plants. Histological analysis revealed giant cells without cytoplasm, disordered neighboring cells, and malformed maturing nematodes in transgenic galls. Curiously, numerous hatching ppJ2 juveniles were often observed near the female body within the transgenic root tissues before egg mass extrusion. All findings strongly suggest that Minc16803 gene is a promising target to engineer agricultural crops for M. incognita resistance through host-induced gene silencing.On-line first. Na publicação: Isabela Tristan Lourenço-Tessutti; Maria C. M. Silva; Leonardo L. P. Macedo; Maria Fatima Grossi-de-Sa

Integrated omic approaches reveal molecular mechanisms of tolerance during soybean and meloidogyne incognita interactions.

The root-knot nematode (RKN), Meloidogyne incognita, is a devastating soybean pathogen worldwide. The use of resistant cultivars is the most effective method to prevent economic losses caused by RKNs. To elucidate the mechanisms involved in resistance to RKN, we determined the proteome and transcriptome profiles from roots of susceptible (BRS133) and highly tolerant (PI595099) Glycine max genotypes 4, 12, and 30 days after RKN infestation. After in silico analysis, we described major defense molecules and mechanisms considered constitutive responses to nematodeinfestation, such as mTOR, PI3K-Akt, relaxin, and thermogenesis. The integrated data allowed us to identify protein families and metabolic pathways exclusively regulated in tolerant soybean genotypes. Among them, we highlighted the phenylpropanoid pathway as an early, robust, and systemic defense process capable of controlling M. incognita reproduction. Associated with this metabolic pathway, 29 differentially expressed genes encoding 11 different enzymes were identified, mainly from the flavonoid and derivative pathways. Based on differential expression in transcriptomic and proteomic data, as well as in the expression profile by RT?qPCR, and previous studies, we selected and overexpressed the GmPR10 gene in transgenic tobacco to assess its protective effect against M. incognita. Transgenic plants of the T2 generation showed up to 58% reduction in the M. incognita reproduction factor. Finally, data suggest that GmPR10 overexpression can be effective against the plant parasitic nematodeM. incognita, but its mechanism of action remains unclear. These findings will help develop new engineered soybean genotypes with higher performance in response to RKN infections

AtDREB2A-CA influences root architecture and increases drought tolerance in transgenic cotton.

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