Romero-Munar Antònia, Aroca Ricardo
Departamento de Microbiología del Suelo y Sistemas Simbióticos, Estación Experimental del Zaidín (CSIC), Profesor Albareda 1, 18008, Granada, Spain.
Departamento de Microbiología del Suelo y Sistemas Simbióticos, Estación Experimental del Zaidín (CSIC), Profesor Albareda 1, 18008, Granada, Spain.
Plant Physiol Biochem. 2023 Mar;196:774-782. doi: 10.1016/j.plaphy.2023.02.027. Epub 2023 Feb 17.
Potassium is one of the principal macronutrients required by all plants, but its mobility is restricted between soil compartments. Numerous studies have shown that Plant Growth Promoting Bacteria (PGPB) can facilitate nutrient uptake. The present work examined the effects of the PGPB (Bacillus megaterium) on rice plants subjected to potassium deprivation. To study only direct effects of B. megaterium, we first checked its lack of capacity to solubilize soil K. Rice plants were provided with 1.5 mM K (100%) or 0.015 mM K (1%) and growth related parameters, nutrient concentrations and gene expression of K transporters were determined. After two weeks, the 1% K treatment reduced growth of non-inoculated plants by about 50% compared with the 100% K treatment. However, there was no effect of reduced K nutrition on growth of inoculated plants. The reduction in growth in non-inoculated plants was accompanied by a similar reduction in K concentration in both roots and leaves and an overall 80% reduction of the plant potassium concentrations. In inoculated plants a 50% reduction occurred only in leaves. The expression of the K transporters HKT1;1, 1;2, 1;5, 2;2, 2;3 and 2;4 was up-regulated by the inoculation of B. megaterium under K deprivation conditions, explaining their higher K tissue concentrations and growth. Thus, the bacterial strain improved plant potassium nutrition without affecting K availability in the soil. The results demonstrate the potential of this bacteria for using as a biofertilizer to reduce the amount of potassium fertilizers to be applied in the field.
钾是所有植物所需的主要大量营养素之一，但其在土壤各组分间的移动性受到限制。众多研究表明，植物促生细菌（PGPB）能够促进养分吸收。本研究考察了PGPB（巨大芽孢杆菌）对缺钾水稻植株的影响。为仅研究巨大芽孢杆菌的直接作用，我们首先检测了其溶解土壤钾的能力缺失情况。给水稻植株提供1.5 mM钾（100%）或0.015 mM钾（1%），并测定生长相关参数、养分浓度以及钾转运蛋白的基因表达。两周后，与100%钾处理相比，1%钾处理使未接种植株的生长降低了约50%。然而，钾营养降低对接种植株的生长没有影响。未接种植株生长的降低伴随着根和叶中钾浓度的类似降低，以及植株钾浓度总体降低80%。在接种植株中，仅叶片中钾浓度降低了50%。在缺钾条件下，接种巨大芽孢杆菌上调了钾转运蛋白HKT1;1、1;2、1;5、2;2、2;3和2;4的表达，这解释了它们较高的钾组织浓度和生长情况。因此，该细菌菌株改善了植物的钾营养，而不影响土壤中的钾有效性。结果证明了这种细菌作为生物肥料以减少田间钾肥施用量的潜力。
