scholarly journals Identification and fine mapping of a novel qGR6.2 locus controlling rice salt tolerance during seed germination

2020 ◽  
Author(s):  
Peng Zeng ◽  
Peiwen Zhu ◽  
Luofeng Qian ◽  
Zefeng Lin ◽  
Xumei Qian ◽  
...  

Abstract The rice growth is strongly affected by salt stress. When exposed to high salt stress, seed germination and seedling establishment are significantly inhibited. Particularly, with the promotion of rice direct-seeding technology in Asia, improving rice salt tolerance during seed germination is of great importance for rice breeding. In this study, an indica rice landrace Wujiaozhan (WJZ) showed significant salt tolerance during seed germination. The dynamic process of seed germination at 300 mM NaCl was observed via the germination rate (GR), seedling percentage (SP), and germination index (GI) from the progeny by crossing WJZ with the salt-sensitive Nipponbare (Nip). By QTL mapping, sixteen quantitative trait loci (QTLs) related to salt-tolerance were detected via a BC1F2 population, including six QTLs for the GR, eight QTLs for the SP, and two QTLs for the GI. Of them, four QTLs, qGR6.1, qGR6.2, qGR10 and qSP10.1, were expressed continuously, especially qGR6.2 and qGR10. Furthermore, twelve significant associated simple sequence repeats (SSR) markers were detected in the F2 population by bulked segregant analysis (BSA). Four SSR markers (RM588, RM190, RM276 and RM5493) were closed to qGR6.1, qGR6.2, qGR6.3, qSP6.1, qSP6.2, qGI6 and qSP8.1 identified by QTL mapping. The major qGR6.2 on chromosome 6 was confirmed via the BC2F2 population, which explained more than 20% phenotype variation of the GR. Fine mapping results displayed that qGR6.2 was narrowed down to a 65.9 kb region between the Z654 and Z619 markers, with eleven candidate genes predicted. Based on the microarray database, six genes (LOC_Os06g10650, LOC_Os06g10660, LOC_Os06g10690, LOC_Os06g10710, LOC_Os06g10730 and LOC_Os06g10750) were differentially expressed after seed imbibition or salt stress. RT-qPCR showed that two genes (LOC_Os06g10650 and LOC_Os06g10750) were significantly induced by salt stress and had different expression patterns in two parents during seed germination.

2020 ◽  
Author(s):  
Peng Zeng ◽  
Peiwen Zhu ◽  
Luofeng Qian ◽  
Xumei Qian ◽  
Yuxin Mi ◽  
...  

Abstract Background Rice growth is frequently affected by salinity. When rice plants are exposed to high salinity, seed germination and seedling establishment are significantly inhibited. In particular, with the promotion of rice direct-seeding in Asia, improving rice salt tolerance during seed germination is of strong importance for rice breeding. Results In this study, we found that the indica rice landrace Wujiaozhan (WJZ) showed a high capability of seed germination under both water (H 2 O) and salt (NaCl) conditions, particularly under high salt stress. The BC 1 F 2 population produced by crossing WJZ with japonica Nipponbare (Nip) was used to evaluate the germination traits under water (H 2 O) and salt (300 mM NaCl) conditions using germination rate (GR) and germination index (GI). A total of 13 quantitative trait loci (QTLs) were identified, including eight QTLs of GR, two QTLs of GI under H 2 O conditions, six QTLs of GR, and three QTLs of GI under 300 mM NaCl conditions. Six QTLs ( qGR6.1 , qGR8.1 , qGR8.2 , qGR10.1 , qGR10.2 and qGI10.1 ) contributed to GR under both H 2 O and 300 mM NaCl conditions. Three QTLs ( qGR6.2 , qGR10.1 and qGR10.2 ) under 300 mM NaCl conditions were identified at different time points of seed germination and shared the same region with qGI6 , qGI10.1 and qGI10.2 for GI. These QTLs could be used to improve seed germination ability via marker-assisted selection (MAS). One major effective salt-tolerance-specific QTL, qGR6.2, on chromosome 6 was further confirmed via the BC 2 F 2 population, which explained more than 20% of the phenotypic variation. Fine mapping results showed that qGR6.2 was narrowed to a 65.9-kb region between the Z654 and Z619 molecular markers, with eleven candidate genes being predicted. Based on the microarray database, there were high transcript abundances of six genes ( LOC_Os06g10650 , LOC_Os06g10660 , LOC_Os06g10690 , LOC_Os06g10710 , LOC_Os06g10730 and LOC_Os06g10750 ) at all developmental stages, and only LOC_Os06g10750 was differentially expressed after salt incubation. RT-qPCR showed that two genes ( LOC_Os06g10650 and LOC_Os06g10750 ) were significantly differentially expressed at 300 mM NaCl during seed germination. This result suggested that LOC_Os06g10650 and LOC_Os06g10750 might be the causal candidate genes for the major effective salt-tolerance-specific QTL qGR6.2 identified in WJZ, which may facilitate map-based cloning and help to elucidate the molecular mechanism underlying salt tolerance during seed germination. Conclusions In our study, we identified 13 QTLs from indica landrace WJZ that confer seed germination traits under water and salt conditions. A major salt-tolerance-specific QTL qGR6.2 was confirmed and fine mapped to a 65.9-kb region flanked by the Z654 and Z619 markers. Our results provide information on the genetic basis of improving salt tolerance during seed germination by MAS.


2020 ◽  
Author(s):  
Peng Zeng ◽  
Peiwen Zhu ◽  
Luofeng Qian ◽  
Xumei Qian ◽  
Yuxin Mi ◽  
...  

Abstract Background Rice growth is frequently affected by salinity. When rice plants are exposed to high salinity, seed germination and seedling establishment are significantly inhibited. In particular, with the promotion of rice direct-seeding in Asia, improving rice salt tolerance during seed germination is of strong importance for rice breeding. Results In this study, we found that the indica rice landrace Wujiaozhan (WJZ) showed a high capability of seed germination under both water (H 2 O) and salt (NaCl) conditions, particularly under high salt stress. The BC 1 F 2 population produced by crossing WJZ with japonica Nipponbare (Nip) was used to evaluate the germination traits under water (H 2 O) and salt (300 mM NaCl) conditions using germination rate (GR) and germination index (GI). A total of 13 quantitative trait loci (QTLs) were identified, including eight QTLs of GR, two QTLs of GI under H 2 O conditions, six QTLs of GR, and three QTLs of GI under 300 mM NaCl conditions. Six QTLs ( qGR6.1 , qGR8.1 , qGR8.2 , qGR10.1 , qGR10.2 and qGI10.1 ) contributed to GR under both H 2 O and 300 mM NaCl conditions. Three QTLs ( qGR6.2 , qGR10.1 and qGR10.2 ) under 300 mM NaCl conditions were identified at different time points of seed germination and shared the same region with qGI6 , qGI10.1 and qGI10.2 for GI. These QTLs could be used to improve seed germination ability via marker-assisted selection (MAS). One major effective salt-tolerance-specific QTL, qGR6.2, on chromosome 6 was further confirmed via the BC 2 F 2 population, which explained more than 20% of the phenotypic variation. Fine mapping results showed that qGR6.2 was narrowed to a 65.9-kb region between the Z654 and Z619 molecular markers, with eleven candidate genes being predicted. Based on the microarray database, there were high transcript abundances of six genes ( LOC_Os06g10650 , LOC_Os06g10660 , LOC_Os06g10690 , LOC_Os06g10710 , LOC_Os06g10730 and LOC_Os06g10750 ) at all developmental stages, and only LOC_Os06g10750 was differentially expressed after salt incubation. RT-qPCR showed that two genes ( LOC_Os06g10650 and LOC_Os06g10750 ) were significantly differentially expressed at 300 mM NaCl during seed germination. This result suggested that LOC_Os06g10650 and LOC_Os06g10750 might be the causal candidate genes for the major effective salt-tolerance-specific QTL qGR6.2 identified in WJZ, which may facilitate map-based cloning and help to elucidate the molecular mechanism underlying salt tolerance during seed germination. Conclusions In our study, we identified 13 QTLs from indica landrace WJZ that confer seed germination traits under water and salt conditions. A major salt-tolerance-specific QTL qGR6.2 was confirmed and fine mapped to a 65.9-kb region flanked by the Z654 and Z619 markers. Our results provide information on the genetic basis of improving salt tolerance during seed germination by MAS.


2005 ◽  
Vol 45 (4) ◽  
pp. 391 ◽  
Author(s):  
B. Zhang ◽  
B. C. Jacobs ◽  
M. O'Donnell ◽  
J. Guo

Salt tolerances of 3 cultivars, Menemen puccinellia (Puccinellia ciliata Bor), Tyrrell and Dundas [tall wheatgrass, Thinopyrum ponticum (Podp.) Z. W. Liu and R. R. C. Wang], were compared with respect to their seed germination, adaptive responses to salt and waterlogging, seedling emergence, plant growth, shoot osmolality and mineral contents in a series of salt-stress experiments. An inverse normal distribution provided good fits for the time to seed germination. Under NaCl stress, 50% of the control (distilled water) seed germination rates of Menemen, Tyrrell and Dundas were achieved in 178.8, 300.9 and 296.8 mmol/L NaCl, respectively. Fifty percent of the control seedling emergence rates of these 3 cultivars were in 92.7, 107.2 and 113.5 mmol/L NaCl, respectively. The seed germination rates of these 3 cultivars under both salt and waterlogging stress were far lower than those germinated only under salt stress at the same salt level. Seed pretreatment by soaking seed in NaCl solutions greatly increased the seed germination rate under salt stress for Menemen and under both salt stress and waterlogging for Dundas. Tyrrell and Dundas were very similar in their tolerance to salt stress, and were significantly (P<0.05) more salt tolerant than Menemen in terms of seed germination and seedling emergence rate. Both shoot height and dry matter of these 3 cultivars were not statistically different among all salt stress levels during the seedling elongation period, indicating that the established plants of these 3 cultivars were very salt tolerant. The salt tolerance mechanisms of these 3 cultivars are possibly related to their abilities to maintain high osmolality in shoots by regulating high sodium and potassium contents, and reducing calcium deficiency under salt stress.


2020 ◽  
Vol 11 ◽  
Author(s):  
Yue Wang ◽  
Pengfei Diao ◽  
Lingqi Kong ◽  
Ruonan Yu ◽  
Man Zhang ◽  
...  

Alfalfa (Medicago sativa L.) is an important forage, and salinity is a major stress factor on its yield. In this study, we show that osmotic stress retards alfalfa seedling growth, while ionic/oxidative stress reduces its seed germination. Ethylene treatment can recover the germination rate of alfalfa seeds under salt stress, while ethylene inhibitor silver thiosulfate exacerbates salt effects. ETH reduces the accumulation of MDA and H2O2 and increases POD activity. ETH and ACC improve the salt tolerance of alfalfa by increasing proline content under salt stress. In contrast, STS inhibits alfalfa seed germination by reducing POD activity. NaCl treatment reduces chlorophyll content in alfalfa leaves, while ETH and ACC can increase the chlorophyll content and promote seedling growth. ETH promotes the growth of alfalfa in saline condition by reducing the expression of MsACO and MsERF8 genes, while increases its germination rate by upregulating MsERF11 gene. Silencing of MsETR2, a putative ethylene receptor gene in alfalfa, abolishes ethylene triggered tolerance to salt stress. In summary, we show that ethylene improves salt tolerance in alfalfa via MsETR2 dependent manner, and we also analyze the regulatory mechanism of ethylene during germination of alfalfa seeds under salt stress.


2021 ◽  
Vol 12 ◽  
Author(s):  
Muhammad Farooq ◽  
Jae-Ryoung Park ◽  
Yoon-Hee Jang ◽  
Eun-Gyeong Kim ◽  
Kyung-Min Kim

Soil salinity is a major problem in agriculture because high accumulation of Na+ ions in plants causes toxicity that can result in yield reduction. Na+/K+ homeostasis is known to be important for salt tolerance in plants. Na+/K+ homeostasis in rice (Oryza sativa L.) involves nine high-affinity K+ transporter (HKT) encoding Na+-K+ symporter, five OsNHX Na+/H+ antiporters, and OsSOS1 Na+/K+ antiporter genes. In the present study, we investigated various molecular and physiological processes to evaluate germination rate, growth pattern, ion content, and expression of OsHKT, OsNHX, and OsSOS1genes related to Na+/K+ homeostasis in different rice genotypes under salt stress. We found a significant increase in the germination percentage, plant vigor, Na+/K+ ratio, and gene expression of the OsHKT family in both the roots and shoots of the Nagdong cultivar and salt-tolerant cultivar Pokkali. In the roots of Cheongcheong and IR28 cultivars, Na+ ion concentrations were found to be higher than K+ ion concentrations. Similarly, high expression levels of OsHKT1, OsHKT3, and OsHKT6 were observed in Cheongcheong, whereas expression levels of OsHKT9 was high in IR28. The expression patterns of OsNHX and OsSOS1 and regulation of other micronutrients differed in the roots and shoots regions of rice and were generally increased by salt stress. The OsNHX family was also expressed at high levels in the roots of Nagdong and in the roots and shoots of Pokkali; in contrast, comparatively low expression levels were observed in the roots and shoots of Cheongcheong and IR28 (with the exception of high OsNHX1 expression in the roots of IR28). Furthermore, the OsSOS1 gene was highly expressed in the roots of Nagdong and shoots of Cheongcheong. We also observed that salt stress decreases chlorophyll content in IR28 and Pokkali but not in Cheongcheong and Nagdong. This study suggests that under salt stress, cultivar Nagdong has more salt-tolerance than cultivar Cheongcheong.


Agronomy ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 1312
Author(s):  
Jia Liu ◽  
Weicong Qi ◽  
Haiying Lu ◽  
Hongbo Shao ◽  
Dayong Zhang

Salt tolerance is an important trait in soybean cultivation and breeding. Plant responses to salt stress include physiological and biochemical changes that affect the movement of water across the plasma membrane. Plasma membrane intrinsic proteins (PIPs) localize to the plasma membrane and regulate the water and solutes flow. In this study, quantitative real-time PCR and yeast two-hybridization were engaged to analyze the early gene expression profiles and interactions of a set of soybean PIPs (GmPIPs) in response to salt stress. A total of 20 GmPIPs-encoding genes had varied expression profiles after salt stress. Among them, 13 genes exhibited a downregulated expression pattern, including GmPIP1;6, the constitutive overexpression of which could improve soybean salt tolerance, and its close homologs GmPIP1;7 and 1;5. Three genes showed upregulated patterns, including the GmPIP1;6 close homolog GmPIP1;4, when four genes with earlier increased and then decreased expression patterns. GmPIP1;5 and GmPIP1;6 could both physically interact strongly with GmPIP2;2, GmPIP2;4, GmPIP2;6, GmPIP2;8, GmPIP2;9, GmPIP2;11, and GmPIP2;13. Definite interactions between GmPIP1;6 and GmPIP1;7 were detected and GmPIP2;9 performed homo-interaction. The interactions of GmPIP1;5 with GmPIP2;11 and 2;13, GmPIP1;6 with GmPIP2;9, 2;11 and GmPIP2;13, and GmPIP2;9 with itself were strengthened upon salt stress rather than osmotic stress. Taken together, we inferred that GmPIP1 type and GmPIP2 type could associate with each other to synergistically function in the plant cell; a salt-stress environment could promote part of their interactions. This result provided new clues to further understand the soybean PIP–isoform interactions, which lead to potentially functional homo- and heterotetramers for salt tolerance.


2018 ◽  
Vol 19 (11) ◽  
pp. 3412 ◽  
Author(s):  
Fenjuan Shao ◽  
Lisha Zhang ◽  
Iain Wilson ◽  
Deyou Qiu

Soil salinization is a matter of concern worldwide. It can eventually lead to the desertification of land and severely damage local agricultural production and the ecological environment. Betula halophila is a tree with high salt tolerance, so it is of importance to understand and discover the salt responsive genes of B. halophila for breeding salinity resistant varieties of trees. However, there is no report on the transcriptome in response to salt stress in B. halophila. Using Illumina sequencing platform, approximately 460 M raw reads were generated and assembled into 117,091 unigenes. Among these unigenes, 64,551 unigenes (55.12%) were annotated with gene descriptions, while the other 44.88% were unknown. 168 up-regulated genes and 351 down-regulated genes were identified, respectively. These Differentially Expressed Genes (DEGs) involved in multiple pathways including the Salt Overly Sensitive (SOS) pathway, ion transport and uptake, antioxidant enzyme, ABA signal pathway and so on. The gene ontology (GO) enrichments suggested that the DEGs were mainly involved in a plant-type cell wall organization biological process, cell wall cellular component, and structural constituent of cell wall molecular function. Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment showed that the top-four enriched pathways were ‘Fatty acid elongation’, ‘Ribosome’, ‘Sphingolipid metabolism’ and ‘Flavonoid biosynthesis’. The expression patterns of sixteen DEGs were analyzed by qRT-PCR to verify the RNA-seq data. Among them, the transcription factor AT-Hook Motif Nuclear Localized gene and dehydrins might play an important role in response to salt stress in B. halophila. Our results provide an important gene resource to breed salt tolerant plants and useful information for further elucidation of the molecular mechanism of salt tolerance in B. halophila.


PLoS ONE ◽  
2021 ◽  
Vol 16 (1) ◽  
pp. e0245505
Author(s):  
Xiaofei Chen ◽  
Ruidong Zhang ◽  
Yifan Xing ◽  
Bing Jiang ◽  
Bang Li ◽  
...  

Sorghum [Sorghum bicolor (L.) Moench] seed germination is sensitive to salinity, and seed priming is an effective method for alleviating the negative effects of salt stress on seed germination. However, few studies have compared the effects of different priming agents on sorghum germination under salt stress. In this study, we quantified the effects of priming with distilled water (HP), sodium chloride (NaCl), potassium chloride (KCl), calcium chloride (CaCl2), and polyethylene glycol (PEG) on sorghum seed germination under 150 mM NaCl stress. The germination potential, germination rate, germination index, vigor index, root length, shoot length, root fresh weight, shoot fresh weight, root dry weight, and shoot dry weight were significantly reduced by salt stress. Different priming treatments alleviated the germination inhibition caused by salt stress to varying degrees, and 50 mM CaCl2 was the most effective treatment. In addition, the mitigation effect of priming was stronger on root traits than on shoot traits. Mitigation efficacy was closely related to both the type of agent and the concentration of the solution. Principal component analysis showed that all concentrations of CaCl2 had higher scores and were clearly distinguished from other treatments based on their positive effects on all germination traits. The effects of the other agents varied with concentration. The priming treatments were divided into three categories based on their priming efficacy, and the 50, 100, and 150 mM CaCl2 treatments were placed in the first category. The 150 mM KCl, 10% PEG, HP, 150 mM NaCl, 30% PEG, and 50 mM KCl treatments were placed in the second category, and the 100 mM NaCl, 100 mM KCl, 20% PEG, and 50 mM NaCl treatments were least effective and were placed in the third category. Choosing appropriate priming agents and methods for future research and applications can ensure that crop seeds germinate healthily under saline conditions.


2021 ◽  
Vol 8 (1) ◽  
Author(s):  
Md. Mia Mukul ◽  
Sheikh Shorif Uddin Ahmed ◽  
Nargis Akter ◽  
Md. Golam Mostofa ◽  
Md. Sohanur Rahman ◽  
...  

Salinity is a serious abiotic stress to Jute and other crop cultivation at saline regions in the world. No salt tolerant Tossa Jute (Corchorus olitorius L.) variety was developed in Bangladesh. Hence, six Tossa Jute accessions were investigated at germination stage against six concentration levels (0.00 or d.H2O, 8.0, 10.0, 12.0, 14.0 and 16.0 dS m-1) of salt (NaCl) using RCB design at Bangladesh Jute Research Institute (BJRI) during March-July, 2020. Jute seeds collected from Gene Bank of BJRI were allowed to germinate under laboratory condition. Seed germination rate was adversely affected as well as delay in germination was prolonged with increasing the salt concentration. In control, seeds were germinated up to 14.0 dS m-1 salt solution. Among six genotypes, Acc. 1141 and Acc. 3801 showed the highest germination rate (86.67 %); Acc. 3801 gave maximum root length (17.0 mm), dry biomass (6.37 mg); and Acc. 1089 showed higher shoot length (10.0 mm), fresh weight (43.93 mg) and salt tolerance index (60.69 %) under 14.0 dS m-1 level. Higher relative salt harm rate (7.14 %) was observed in both Acc. 1141 and Acc. 3801 under 14.0 dS m-1 salinity indicating highly tolerance to salinity. Acc. 3801 and Acc. 1141 were found good for germination under salt stresses; Acc. 3801, Acc. 1089 for fiber yield and salt tolerance; Acc. 3801 and Acc. 1407 for higher fiber yield. Acc. 3801 was found good for salt tolerance and fiber yield content. The genotypes with good desirable characters would be used as breeding materials to develop high yielding salt tolerant Tossa Jute variety.


2019 ◽  
Vol 19 (1) ◽  
Author(s):  
Zemao Yang ◽  
Youxin Yang ◽  
Zhigang Dai ◽  
Dongwei Xie ◽  
Qing Tang ◽  
...  

Abstract Background Jute (Corchorus spp.) is the most important natural fiber crop after cotton in terms of cultivation area and production. Salt stress greatly restricts plant development and growth. A high-density genetic linkage map is the basis of quantitative trait locus (QTLs) mapping. Several high-density genetic maps and QTLs mapping related to salt tolerance have been developed through next-generation sequencing in many crop species. However, such studies are rare for jute. Only several low-density genetic maps have been constructed and no salt tolerance-related QTL has been mapped in jute to date. Results We developed a high-density genetic map with 4839 single nucleotide polymorphism markers spanning 1375.41 cM and an average distance of 0.28 cM between adjacent markers on seven linkage groups (LGs) using an F2 jute population, LGs ranged from LG2 with 299 markers spanning 113.66 cM to LG7 with 1542 markers spanning 350.18 cM. In addition, 99.57% of gaps between adjacent markers were less than 5 cM. Three obvious and 13 minor QTLs involved in salt tolerance were identified on four LGs explaining 0.58–19.61% of the phenotypic variance. The interval length of QTL mapping varied from 1.3 to 20.2 cM. The major QTL, qJST-1, was detected under two salt stress conditions that explained 11.81 and 19.61% of the phenotypic variation, respectively, and peaked at 19.3 cM on LG4. Conclusions We developed the first high-density and the most complete genetic map of jute to date using a genotyping-by-sequencing approach. The first QTL mapping related to salt tolerance was also carried out in jute. These results should provide useful resources for marker-assisted selection and transgenic breeding for salt tolerance at the germination stage in jute.


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