ABSTRACT
MAIN CONCLUSION: The overexpression of the GmGlb1-1 gene reduces plant susceptibility to Meloidogyne incognita. Non-symbiotic globin class #1 (Glb1) genes are expressed in different plant organs, have a high affinity for oxygen, and are related to nitric oxide (NO) turnover. Previous studies showed that soybean Glb1 genes are upregulated in soybean plants under flooding conditions. Herein, the GmGlb1-1 gene was identified in soybean as being upregulated in the nematode-resistant genotype PI595099 compared to the nematode-susceptible cultivar BRS133 during plant parasitism by Meloidogyne incognita. The Arabidopsis thaliana and Nicotiana tabacum transgenic lines overexpressing the GmGlb1-1 gene showed reduced susceptibility to M. incognita. Consistently, gall morphology data indicated that pJ2 nematodes that infected the transgenic lines showed developmental alterations and delayed parasitism progress. Although no significant changes in biomass and seed yield were detected, the transgenic lines showed an elongated, etiolation-like growth under well-irrigation, and also developed more axillary roots under flooding conditions. In addition, transgenic lines showed upregulation of some important genes involved in plant defense response to oxidative stress. In agreement, higher hydrogen peroxide accumulation and reduced activity of reactive oxygen species (ROS) detoxification enzymes were also observed in these transgenic lines. Thus, based on our data and previous studies, it was hypothesized that constitutive overexpression of the GmGlb1-1 gene can interfere in the dynamics of ROS production and NO scavenging, enhancing the acquired systemic acclimation to biotic and abiotic stresses, and improving the cellular homeostasis. Therefore, these collective data suggest that ectopic or nematode-induced overexpression, or enhanced expression of the GmGlb1-1 gene using CRISPR/dCas9 offers great potential for application in commercial soybean cultivars aiming to reduce plant susceptibility to M. incognita.
Subject(s)
Arabidopsis , Tylenchoidea , Animals , Globins/metabolism , Hydrogen Peroxide/metabolism , Nitric Oxide/metabolism , Oxygen/metabolism , Reactive Oxygen Species/metabolism , Glycine max/genetics , Glycine max/metabolism , Tylenchoidea/geneticsABSTRACT
A field experiment in Cambé-PR was carried out with 20 treatments arranged in split plot with 4 replications in a randomized complete block design, using the soybean cultivar BRS 133. The treatments were CALPOT (0.0 and 2.35 t.ha-1) in the main plots, source of phosphorus (STP and SSP) in sub-plot, dosages of phosphorus (40 and 60 kg of P2O5.ha-1) in the sub-sub-plots, and density of plants (9 and 18 plants m-1) in the sub-sub-sub-plots. The greatest effect was on plant population, with the highest dry matter accumulation for the density of 200.000 plants ha-1 (9 plants m-1). The basic cation equilibrium in the soil helped to maximize this effect.
Num experimento de campo em Cambe, PR (23º1645 S, 51º1645 W e 650 m) com o cultivar de soja BRS 133, foram aplicados 20 tratamentos em parcelas sub-sub-divididas, com quatro repetições em delineamento de blocos casualizados. Os tratamentos foram combinados, potássio no momento da calagem - CALPOT (0,0 e 2,35 t.ha-1) nas parcelas, fontes de fósforo (STP e SSP) nas subparcelas, doses de P (40 e 60 kg. P2O5.ha-1) nas sub-sub-parcelas e densidade de plantas (9 e 18 plantas.m-1) nas sub-sub-sub-parcelas. De acordo com as variáveis analisadas, os maiores efeitos se restringiram à diferença entre as populações de plantas, com vantagem significativa para o acúmulo de matéria seca por planta (g) para população de 200.000 plantas por hectare (9 plantas por m). O equilíbrio de bases no solo por meio da aplicação de CALPOT contribui para maximizar esses efeitos.
ABSTRACT
A field experiment in Cambé-PR was carried out with 20 treatments arranged in split plot with 4 replications in a randomized complete block design, using the soybean cultivar BRS 133. The treatments were CALPOT (0.0 and 2.35 t.ha-1) in the main plots, source of phosphorus (STP and SSP) in sub-plot, dosages of phosphorus (40 and 60 kg of P2O5.ha-1) in the sub-sub-plots, and density of plants (9 and 18 plants m-1) in the sub-sub-sub-plots. The greatest effect was on plant population, with the highest dry matter accumulation for the density of 200.000 plants ha-1 (9 plants m-1). The basic cation equilibrium in the soil helped to maximize this effect.
Num experimento de campo em Cambe, PR (23º1645 S, 51º1645 W e 650 m) com o cultivar de soja BRS 133, foram aplicados 20 tratamentos em parcelas sub-sub-divididas, com quatro repetições em delineamento de blocos casualizados. Os tratamentos foram combinados, potássio no momento da calagem - CALPOT (0,0 e 2,35 t.ha-1) nas parcelas, fontes de fósforo (STP e SSP) nas subparcelas, doses de P (40 e 60 kg. P2O5.ha-1) nas sub-sub-parcelas e densidade de plantas (9 e 18 plantas.m-1) nas sub-sub-sub-parcelas. De acordo com as variáveis analisadas, os maiores efeitos se restringiram à diferença entre as populações de plantas, com vantagem significativa para o acúmulo de matéria seca por planta (g) para população de 200.000 plantas por hectare (9 plantas por m). O equilíbrio de bases no solo por meio da aplicação de CALPOT contribui para maximizar esses efeitos.