Enzyme expression in indica and japonica rice cultivars under saline stress

Abstract

ABSTRACT. The southern State of Rio Grande do Sul (RS) is the main rice producer in Brazil with a 60% participation of the national production and 86% participation of the region. Rice culture irrigation system is done by flooding, which leads to soil salinization, a major environmental constraint to production since it alters the plants' metabolism exposed to this type of stress. The indica cultivar, widely used in RS, has a higher sensitivity to salinity when compared to that of the japonica cultivar in other physiological aspects. Current research analyzes enzymes expression involved in salt-subjected indica and japonica rice cultivars' respiration. Oryza sativa L. spp. japonica S.Kato (BRS Bojuru, IAS 12-9 Formosa and Goyakuman) and Oryza sativa L. spp. indica S. Kato (BRS Taim-7, BRS Atalanta and BRS Querencia) were the cultivars employed. Seedlings were transferred to 15 L basins containing 50% Hoagland nutrient solution increased by 0, 25, 50, 75 and 100 mM NaCl, and collected at 14, 28 and 42 days after transfer (DAT). Plant tissues were macerated and placed in eppendorf tubes with Scandálios extractor solution. Electrophoresis was performed in 7% of the polyacrylamide gels in vertical vats. Bands were revealed for the following enzymes systems: esterase, alcohol dehydrogenase, phosphoglucoisomerase, malate dehydrogenase, malic enzyme and alpha amylase. The enzymes expression was greater in subspecies japonica, with more intense bands in proportion to salinity increase. Results show that enzyme systems are involved in the salinity defense mechanisms in O. sativa spp. japonica cultivar.Keywords: electrophoresis, isoenzyme, krebs cycle, O. sativa L., salinity.Expressão de enzimas em cultivares de arroz indica e japonica sob estresse salino RESUMO. O Estado do Rio Grande do Sul (RS) destaca-se como principal produtor de arroz, participando com 60% da produção nacional e 86% da regional. O sistema de irrigação da cultura é por inundação, que induz o solo à salinização, um dos maiores limitadores ambientais à produção, alterando o metabolismo da plantas expostas a este tipo de estresse. As cultivares indicas amplamente utilizadas no RS demonstram maior suscetibilidade à salinidade quando comparadas às japonicas em outros aspectos fisiológicos. O objetivo da pesquisa foi analisar a expressão de enzimas envolvidas na respiração de cultivares de arroz, indica e japonica, submetidas à salinidade. Foram utilizadas cultivares de Oryza sativa L. spp. japonica S. Kato (BRS Bojuru, IAS 12-9 Formosa e Goyakuman) e de Oryza sativa L. spp. indica S. Kato (BRS-7 Taim, BRS Querência e BRS Atalanta). As plântulas foram transferidas para bacias de 15 L, contendo solução nutritiva de Hoagland meia força acrescida de 0, 25, 50, 75 e 100 mM de NaCl. A coleta foi aos 14, 28 e 42 dias. Os tecidos vegetais foram macerados e colocados em tubos eppendorf com solução extratora de Scandálios. A eletroforese foi realizada em géis de poliacrilamida 7% em cubas eletroforéticas verticais. As bandas foram reveladas para os sistemas enzimát...

A consortium of rhizobacterial strains and biochemical growth elicitors improve cold and drought stress tolerance in rice (Oryza sativa L.)

“…It is estimated that 50% of world rice production affected more or less by drought (Bouman et al 2005). As previously reported, the yield loss due to cold stress is up to 80% in Japan (Shimono et al 2007), 26% in Korea (Lee 2001), 25% in Brazil (1997Lima et al 2012;Cruz et al 2013), while in 2001, the Australian rice industry suffered an average loss of Aus $23.2 million per year from cold damage (Farrell et al 2001). It has been repeatedly found that certain biochemicals, known as effectors/elicitors, applied to plants in low concentrations can activate biochemical, genetic and physical defence mechanisms (Garcia-Brugger et al 2006).…”

“…), 26% in Korea (Lee ), 25% in Brazil (1997, 2011, 2012; Lima et al . ; Cruz et al . ), while in 2001, the Australian rice industry suffered an average loss of Aus $23.2 million per year from cold damage (Farrell et al .…”

Effect of Gibberellic Acid (GA3) on the Yield Attributing Traits during a Cold Period in Rice

“…Cold tolerance is one of the major qualities, a rice cultivar is expected to have since the low temperatures have caused significant yield losses in many parts of the world [1]. Low temperatures during the flowering stage cause incomplete panicle exertion, spikelet sterility, and Original Research Article degeneration of the spikelet resulting in low grain formation [2].…”

Avoiding damage and achieving cold tolerance in rice plants

“…In this region, as well as in Uruguay and Argentina, indica rice accounts for almost the totality of cultivated rice. Low temperature can reduce up to 25% of the final yield (Bierlen et al 1997;Clayton and Neves 2011;Lima et al 2012).…”