scholarly journals Effect of salt stress on physiological response and leaf polyamine content in NERICA rice seedlings

2011 ◽  
Vol 57 (No. 12) ◽  
pp. 571-576 ◽  
Author(s):  
A. Yamamoto ◽  
H. Sawada ◽  
I.S. Shim ◽  
K. Usui ◽  
S. Fujihara
Keyword(s):  
Salt Stress ◽  
Salt Tolerance ◽  
Rice Variety ◽  
West African ◽  
Rice Seedlings ◽  
Rice Varieties ◽  
Stress Injury ◽  
African Rice ◽  
Polyamine Content ◽  
Vigorous Growth

NERICA is a new African rice variety, developed by the West African Rice Development Association (WARDA) in 1990s. NERICA rice shows both vigorous growth and tolerance of stressors such as drought and disease. The purpose of this study was to clarify the physiological and biochemical responses to salt stress of NERICA rice seedlings. The degree of growth inhibition caused by salt stress was small in NERICA rice varieties as compared with japonica Nipponbare. Na accumulation in leaf blades was high in salt-sensitive varieties. Accumulation of proline, a known compatible solute, was also induced by salt stress, especially in salt-sensitive varieties; it was thought that this accumulation was brought on salt-stress injury. The contents of polyamines, especially spermidine, were high in the pre-stressed leaf blades of NERICA rice seedlings. After the salt-stress treatment, the polyamine content of leaf blades differed with the degree of salt tolerance of the NERICA rice seedlings. These results suggested that the salt tolerance of NERICA rice seedlings might be associated not only with the regulation of Na absorption and translocation but also with their ability to maintain leaf polyamine levels under salt-stress conditions.  

scholarly journals Improvement of a RD6 Rice Variety for Blast Resistance and Salt Tolerance through Marker-Assisted Backcrossing

Agronomy ◽  
2020 ◽  
Vol 10 (8) ◽  
pp. 1118 ◽  
Author(s):  
Korachan Thanasilungura ◽  
Sukanya Kranto ◽  
Tidarat Monkham ◽  
Sompong Chankaew ◽  
Jirawat Sanitchon
Keyword(s):  
Salt Stress ◽  
Salt Tolerance ◽  
Agronomic Traits ◽  
Blast Resistance ◽  
Rice Variety ◽  
Gene Pyramiding ◽  
Blast Disease ◽  
Resistance Qtls ◽  
Rice Varieties ◽  
Marker Assisted Backcrossing

RD6 is one of the most favorable glutinous rice varieties consumed throughout the north and northeast of Thailand because of its aroma and softness. However, blast disease and salt stress cause decreases in both yield quantity and quality during cultivation. Here, gene pyramiding via marker-assisted backcrossing (MAB) using combined blast resistance QTLs (qBl 1, 2, 11, and 12) and Saltol QTL was employed in solving the problem. To pursue our goal, the RD6 introgression line (RGD07005-12-165-1), containing four blast-resistant QTLs, were crossed with the Pokkali salt tolerant variety. Blast resistance evaluation was thoroughly carried out in the fields, from BC2F2:3 to BC4F4, using the upland short-row and natural field infection methods. Additionally, salt tolerance was validated in both greenhouse and field conditions. We found that the RD6 “BC4F4 132-12-61” resulting from our breeding programme successfully resisted blast disease and tolerated salt stress, while it maintained the desirable agronomic traits of the original RD6 variety. This finding may provide a new improved rice variety to overcome blast disease and salt stress in Northeast Thailand.

scholarly journals Identification of Key Genes in ‘Luang Pratahn’, Thai Salt-Tolerant Rice, Based on Time-Course Data and Weighted Co-expression Networks

2021 ◽  
Vol 12 ◽  
Author(s):  
Pajaree Sonsungsan ◽  
Pheerawat Chantanakool ◽  
Apichat Suratanee ◽  
Teerapong Buaboocha ◽  
Luca Comai ◽  
...  
Keyword(s):  
Salt Stress ◽  
Salt Tolerance ◽  
Stress Responses ◽  
Time Course ◽  
Rice Variety ◽  
Enrichment Analysis ◽  
Normal Growth ◽  
Growth Conditions ◽  
Pathway Enrichment Analysis ◽  
Key Genes

Salinity is an important environmental factor causing a negative effect on rice production. To prevent salinity effects on rice yields, genetic diversity concerning salt tolerance must be evaluated. In this study, we investigated the salinity responses of rice (Oryza sativa) to determine the critical genes. The transcriptomes of ‘Luang Pratahn’ rice, a local Thai rice variety with high salt tolerance, were used as a model for analyzing and identifying the key genes responsible for salt-stress tolerance. Based on 3' Tag-Seq data from the time course of salt-stress treatment, weighted gene co-expression network analysis was used to identify key genes in gene modules. We obtained 1,386 significantly differentially expressed genes in eight modules. Among them, six modules indicated a significant correlation within 6, 12, or 48h after salt stress. Functional and pathway enrichment analysis was performed on the co-expressed genes of interesting modules to reveal which genes were mainly enriched within important functions for salt-stress responses. To identify the key genes in salt-stress responses, we considered the two-state co-expression networks, normal growth conditions, and salt stress to investigate which genes were less important in a normal situation but gained more impact under stress. We identified key genes for the response to biotic and abiotic stimuli and tolerance to salt stress. Thus, these novel genes may play important roles in salinity tolerance and serve as potential biomarkers to improve salt tolerance cultivars.

scholarly journals Screening and evaluation of upland rice (Oryza sativa L.) varieties in inundated soil

2018 ◽  
Vol 51 (2) ◽  
pp. 63-69
Author(s):  
Sunday Ojo Adigbo ◽  
Philip Joseph Osadebay ◽  
Innocent Iseghohi ◽  
Cornelius Idowu Alarima ◽  
Nnennaya Ogechi Agbenin ◽  
...  
Keyword(s):  
Upland Rice ◽  
Oryza Sativa L ◽  
Rice Variety ◽  
Rice Varieties ◽  
Inland Valley ◽  
Short Period ◽  
Maturity Period ◽  
Vigorous Growth ◽  
Number Of Leaves ◽  
Screen House

Abstract Poor germination and subsequent low grain yield of dry seeded upland rice in the existing anaerobic and short niche between lowland rice and dry season crops in the inland valley necessitate the screening of 19 rice varieties. The identification of vigorous growth and short duration upland rice variety in anaerobic condition would optimize this niche. The potted experiment was carried out in the screen house of the Department of Crop Science and Horticulture, Federal University Oye-Ekiti, Ikole campus in 2015 to screen and evaluate the performance of upland rice varieties in inundated soils with a view to selecting the suitable variety or varieties that will fit into the existing niche in the inland valley. The experiment was laid in a complete randomization design and replicated three times. The number of leaves, biomass and grain weight plant−1 of the varieties were significantly (P ≤ 0.05 %) different. The number of tillers observed in WAB 56-104, NERICA 4, NERICA 6, NERICA 3, NERICA 5, NERICA 10, NERICA 9, ARICA 4 NERICA 1, FARO 63, FARO 65 and NERICA 8 varieties were significantly (P < 0.05) lower than those of Igbemo varieties. The numbers of days to 50 % flowering of NERICA 1, NERICA 2, NERICA 10, NERICA 5, NERICA 9, NERICA 3, NERICA 7, NERICA 8, ARICA 4 and WAB 56-104 varieties were the lowest. Although Igbemo brown, Igbemo white varieties had the highest grain yields per plant, their maturity period exceeded the short period. Thus, NERICA 2 and NERICA 5 varieties which had lower number of days to flowering could be considered as candidate varieties that can be optimized in the niche in question.

scholarly journals QTL mapping and candidate gene identification in rice using a Kalarata-Azucena population under salt stress

2020 ◽  
Author(s):  
Marjorie P. de Ocampo ◽  
Ho Viet The ◽  
Michael J. Thomson ◽  
Shiro Mitsuya ◽  
Akira Yamauchi ◽  
...  
Keyword(s):  
Salt Stress ◽  
Salt Tolerance ◽  
Candidate Gene ◽  
Candidate Genes ◽  
Evaluation System ◽  
Average Distance ◽  
Chlorophyll Concentration ◽  
Interval Mapping ◽  
Chromosome 1 ◽  
Rice Varieties

Abstract Background Salt stress is a major constraint across large rice production areas in Asia, because of the high sensitivity of modern rice varieties. To identify quantitative trait loci (QTL) associated with salt tolerance in rice, we developed an F2 population from a cross between the salt-tolerant landrace, Kalarata, and the salt-sensitive parent, Azucena. An F2 population was used for DNA extraction, and F2:3 families from this population were screened in a phytotron in a saline nutrient solution at the seedling stage. Results After 2 weeks at an EC of 12 dS m− 1, the F2:3 families were scored for salt tolerance using IRRI’s Standard evaluation system (SES). Growth, biomass, Na+ and K+ concentrations in leaf tissues, and chlorophyll concentration were determined. A genetic linkage map was constructed with 151 SSRs and InDel markers, which cover 1463 cM with an average distance of 9.69 cM between loci. A total of 13 QTL were identified using Composite Interval Mapping for 16 traits. The short arm of chromosome 1 had the highest density of QTL associated with salt tolerance, which coincides with the Saltol locus; emphasizing the importance of this locus for candidate gene discovery and for use in rice breeding. Several novel QTL were identified on other chromosomes. Conclusions The novel QTL identified in this study constitute future targets for molecular breeding, to combine them with other QTLs identified before, for higher and stable performance of rice varieties in salt affected soils. Candidate genes for the large effect QTL on chromosome 3 were found to be involved in diverse biological processes, cellular components, and molecular functions. Several candidate genes in this locus were functionally associated with salt stress tolerance and should further be considered for genetic improvement of rice varieties.

Nodule-Like Structures Induced on the Roots of Rice Seedlings by Addition of the Synthetic Auxin 2,4-Dichlorophenoxyacetic Acid

1993 ◽  
Vol 20 (6) ◽  
pp. 705 ◽  
Author(s):  
RW Ridge ◽  
KM Ride ◽  
BG Rolfe
Keyword(s):  
Early Stage ◽  
Lateral Roots ◽  
Rice Variety ◽  
Root Surface ◽  
Dichlorophenoxyacetic Acid ◽  
Internal Tissue ◽  
Rice Seedlings ◽  
Rice Varieties ◽  
Close Proximity ◽  
2,4 Dichlorophenoxyacetic Acid

Nodule-like structures were induced on rice varieties Calrose and Pelde using 2,4-dichlorophenoxyacetic acid (2,4-D) in a concentration range of 2.5 × 10-6 M to 1 × 10-5M. The nodule-like structures appeared to result from the fusion of multiple meristems induced in very close proximity to each other. The internal tissue differentiation of some of the nodule-like structures was found to be similar to that of both Parasponia nodules and some kinds of determinate legume nodules. These spheroid nodule-like structures, similar in external morphology to determinate legume nodules, showed no internal infection or colonisation by Rhizobium strain NGR 234 or the Azorhizobium strain ORS 571. However, on the rice variety Calrose, the strain ORS 571 sometimes colonised extensively the surface of the nodule- like structures, in comparison to levels found on emerging lateral roots and to the root surface of the same plants. The strain NGR 234 did not colonise the surface of the nodule-like structures. The synthetic phytohormone 2,4-D also induced a range of other phenomena, including various levels of fusion of primordia and structures with a callus-like surface instead of an epidermis, but with a differentiated internal anatomy. These experiments indicate that tissue development in some types of nodule is the result of a number of meristems fusing together at a single site, and at a very early stage in development.

Effects of Soda Saline-Alkali Stress on Physiological Characteristics of Rice in Different Concentrations

2014 ◽  
Vol 1010-1012 ◽  
pp. 1225-1229
Author(s):  
Ming Xia Zhu ◽  
Feng Jin ◽  
Xi Wen Shao ◽  
Xian Ying Gao ◽  
Yan Qiu Geng ◽  
...  
Keyword(s):  
Salt Stress ◽  
Sugar Content ◽  
Rice Variety ◽  
Soluble Sugar ◽  
Soil Improvement ◽  
Salt Resistance ◽  
Physiological Characteristics ◽  
Alkali Stress ◽  
Rice Varieties ◽  
Reference Index

Taking Changbai 9 and Changbai 22 as experiment material, using pot experiment, to study of different concentration effect of saline alkali stress on physiological characteristics of rice in different growth periods. The results showed that, effect of saline alkali stress on the physiological characteristics of the same rice variety and soil characteristics of different resistant rice varieties are different. Weak salt resistance of Changbai 22 of chlorophyll , soluble sugar and MDA of salt stress more sensitive than saline resistance strong of Changbai 9,and the change trend of the physiological indexes of two cultivars under saline alkali stress is consistent, with the increasing concentration of salt stress, leaf chlorophyll content, soluble sugar content and soluble protein content firstly increased and then decreased,while the MDA concentration showed an increasing trend. At the same time with the increase of salt stress concentration, accumulation of soluble sugar in leaves of Changbai 9 increased even more than Changbai 22,indicating the Changbai 9 may be mainly through the accumulation of soluble sugar to alleviate the toxic effects of osmotic stress. This study can be used as an important reference index for soda saline alkali soil rice planting, soil improvement and comprehensive utilization.

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