Response to in vitro salt stress in sugarcane is conditioned by concentration and condition of exposure to NaCl

Abstract

Salinity is one of the major environmental stress factors that affect crop productivity, as well as interfering with plant growth and development, resulting in reduced production quality. Given this, we highlight the importance of research in response to plants subjected to salt stress in order to assess the physiological and biochemical behavior of genotypes, with the objective of selecting the more tolerant. One way to ensure the uniformity of the response of the plants is through in vitro cultivation, which allows control of the cultivation conditions. Therefore, the objective of this work was to evaluate the response of two commercial varieties of sugar cane exposed to saline stress in different conditions (gradual and abrupt). Two varieties of sugarcane (RB931011 and RB872552) were subjected to in vitro salt stress by NaCl (56 mM and 112 mM), either gradually or suddenly. The responses of the enzymatic antioxidant system (catalase, peroxidases and ascorbate peroxidase) and free proline, as well as the Na + and K + contents, were assessed 30 days after the beginning of the treatments. Differences were observed in the responses of the varieties as a function of the induction mode of salt stress, graded or by shock, rather than as a function of the NaCl concentrations in the culture medium. The stress response is therefore conditioned not only by salt concentration, but also by the form of exposure to salt.Keywords: antioxidant enzymes, in vitro culture, oxidative stress, salinity. RESUMENLa salinidad es uno de los principales factores de estrés ambiental, además de interferir en el crecimiento de las plantas perjudica directamente la producción agrícola. En ese contexto, se destaca la importancia de investigaciones direccionadas a la respuesta de las plantas sometidas al estrés salino, con el fin de evaluar el comportamiento fisiológico y bioquímico con el objetivo de seleccionar genotipos tolerantes a dicha condición. Una de las técnicas más utilizadas para uniformizar la respuesta de las plantas a una condición en particular es el cultivo de tejidos in vitro. Por lo tanto, el objetivo de este estudio fue evaluar la respuesta de dos variedades comerciales de caña de azúcar (RB931011 e RB872552) expuestas a estrés salino con NaCl (56 mM e 112 mM) en diferentes condiciones, gradual y abrupta. Las respuestas del sistema antioxidante enzimático (catalasa, peroxidasa y ascorbato peroxidasa) y prolina libre, asi como las concentraciones de Na + e K + fueron evaluadas 30 días después del inicio de los tratamientos. Fueron observadas diferencias en la respuesta de las variedades en función del modo de inducción del estrés salino, graduado o abrupto, y no solo en función de las concentraciones de NaCl en el medio de cultivo. La respuesta al estrés es condicionada no solo por la concentración de sal sino también por la forma de exposición al medio salino.Palabras clave: cultivo in vitro, enzimas antioxidantes, estrés oxidativo, salinidad.

Expression of Cowpea VuWRKY21 and VuWRKY87 Genes in Arabidopsis thaliana Confers Plant Tolerance to Salt Stress

“…Plants use several strategies to detoxify the cell from ROS [53], including the synthesis of low molecular weight compounds and antioxidant enzymes [54], such as catalase, which is considered one of the most important enzymes for the intracellular regulation of peroxide levels under abiotic stresses [55]. At the initial times, the highest specific activity of catalase (CAT) was verified, being around 40% higher in the VuWRKY21 lines at 2 h and, on average, 140% higher at 1 h VuWRKY87 transformed lines.…”

Differential Physiological Traits, Ion Homeostasis and Cane Yield of Sub-Tropical Sugarcane Varieties in Response to Long-Term Salinity Stress

“…Under saline conditions, plants accumulated Na + at the expense of K + and an optimal Na + /K + ratio is essential for maintaining the enzymatic reactions in the cytoplasm [39]. Since higher Na + /K + indicates excess accumulation of Na + which interfere with the energy utilization pattern that plants exploit to acquire water from the soil, osmotic adjustments might have resulted in reduced plant growth and yield [40][41][42][43]. Among different studied genotypes, Co 0238, Co 05011, Co 0118 and Co 06034 maintained low Na + /K + in all the studied plant parts, due to lower sodium absorption, retaining higher membrane integrity, higher osmolytes and preferential higher K + uptake.…”

Biochemical, physiological and growth changes in response to in vitro salinity in sugarcane

“…Gandonou et al (2005) studying varieties of sugarcane under conditions of in vitro saline stress, observed that both the sensitive variety CP65-357 and the resistant variety NCo310 behaved similarly, accumulating greater amounts of proline in the more severe saline treatments (102 mM). Granja et al (2018) evaluating the response of two commercial varieties of sugarcane (RB931011 and RB872552), exposed to in vitro salt stress by NaCl (56 mM and 112 mM), concluded that the proline content increased only in plants submitted to treatment with 112mM of NaCl, granting to the sugarcane varieties a greater protection against salt stress. These results reinforce the results found in the present study, in relation to the proline increase in plants submitted to increasing levels of NaCl.…”