scholarly journals Assessment of cold stress tolerance in maize through quantitative trait locus, genome-wide association study and transcriptome analysis

2021 ◽  
Vol 49 (4) ◽  
pp. 12525
Author(s):  
Syed F.A. GILLANI ◽  
Adnan RASHEED ◽  
Gai YUHONG ◽  
Wei JIAN ◽  
Wang Y. XIA ◽  
...  

Genome-wide association study (GWAS) has become a widely accepted strategy for decoding genotype phenotype associations in many species thanks to advances in next-generation sequencing (NGS) technologies. Maize is an ideal crop for GWAS and significant progress has been made in the last decade. This review summarizes current GWAS efforts in maize functional genomics research and discusses future prospects in the omics era. The general goal of GWAS is to link genotypic variations to corresponding differences in phenotype using the most appropriate statistical model in a given population. The current review also presents perspectives for optimizing GWAS design and analysis. GWAS analysis of data from RNA, protein, and metabolite-based omics studies is discussed, along with new models and new population designs that will identify causes of phenotypic variation that have been hidden to date. The detailed that low temperature in maize seedlings altogether restricts germination and seedlings' development and destabilizes the cancer prevention agent safeguard component. Cold pressure adversely influences root morphology, photosystem II (PS II) effectiveness, chlorophyll substance, and leaf region. A short scene of low temperature stress (for example, under 10 °C for 7 days) during the V6–V9 maize development stages can fundamentally defer the anthesis commencement. Among the morphological reactions by focused on maize plants, low temperature stress causes strange tuft development in maize, along these lines influencing the fertilization and grain filling measures. Hence, problematic temperatures can cause a genuine yield decrease if happening at basic conceptive stages, as plants allocate over half of their photosynthesis to foster grains during this stage until physiological development. Low temperature stress fundamentally diminishes the plant stature and absolute yield biomass of maize. Leaf improvement turns out to be delayed in chilly focused on plants because of a drawn-out cell cycle and diminished pace of mitosis.  The joint and continuous efforts of the whole community will enhance our understanding of maize quantitative traits and boost crop molecular breeding designs.

2021 ◽  
Author(s):  
Caijing Li ◽  
Jindong Liu ◽  
Jianxin Bian ◽  
Tao Jin ◽  
Baoli Zou ◽  
...  

Abstract Background: Rice is a crop that is very sensitive to low temperature, and its morphological development and production are greatly affected by low temperature. Therefore, understanding the genetic basis of cold tolerance in rice is of great significance for mining favorable genes and cultivating excellent rice varieties. However, there were limited studies focusing on cold tolerance at the bud burst stage, therefore, considerable attention should be paid to the genetic basis of cold tolerance at the bud burst stage (CTBB).Results: In this study, a natural population consisting of 211 rice landraces collected from 15 provinces of China and other countries were firstly used to evaluate the cold tolerance at the bud burst stage. Population structure analysis showed that this population divided into three groups and was rich in genetic diversity. Our evaluation results confered that the japonica rice was more tolerance to cold at the bud burst stage than indica rice. Genome-wide association study (GWAS) were performed through the phenotypic data of 211 rice landraces and 36,727 SNPs dataset under a mixed linear model, and 12 QTLs (P < 0.0001) were identified according to the seedling survival rate (SSR) treated at 4 ℃, in which there are five QTLs (qSSR2-2, qSSR3-1, qSSR3-2, qSSR3-3 and qSSR9) which were co-located with previous studies, and seven QTLs (qSSR2-1, qSSR3-4, qSSR3-5, qSSR3-6, qSSR3-7, qSSR4 and qSSR7) which were reported for the first time. Among these QTLs, qSSR9, harboring the highest-peak SNP, explained biggest phenotypic variation. Through bioinformatics analysis, five genes (LOC_Os09g12440, LOC_Os09g12470, LOC_Os09g12520, LOC_Os09g12580 and LOC_Os09g12720) were nominated as candidates for qSSR9. Conclusion: This natural population consisting of 211 rice landraces with high density SNPs will serve as a better choice for identifying rice QTLs/genes in future, and the detected QTLs associated with cold tolerance in rice bud burst stage will be conducive to further mining favorable genes and breeding of rice varieties under cold stress.


2021 ◽  
Vol 8 (1) ◽  
Author(s):  
Xiaokang Zhuo ◽  
Tangchun Zheng ◽  
Suzhen Li ◽  
Zhiyong Zhang ◽  
Man Zhang ◽  
...  

AbstractWeeping Prunus mume (mei) has long been cultivated in East Asia for its specific ornamental value. However, little is known about the regulatory mechanism of the weeping trait in mei, which limits molecular breeding for the improvement of weeping-type cultivars. Here, we quantified the weeping trait in mei using nested phenotyping of 214 accessions and 342 F1 hybrids. Two major associated loci were identified from the genome-wide association study (GWAS), which was conducted using 3,014,409 single nucleotide polymorphisms (SNPs) derived from resequencing, and 8 QTLs and 55 epistatic loci were identified from QTL mapping using 7,545 specific lengths amplified fragment (SLAF) markers. Notably, an overlapping PmWEEP major QTL was fine mapped within a 0.29 Mb region on chromosome 7 (Pa7), and a core SNP locus closely associated with the weeping trait was screened and validated. Furthermore, a total of 22 genes in the PmWEEP QTL region were expressed in weeping or upright mei based on RNA-seq analysis. Among them, only a novel gene (Pm024213) containing a thioredoxin (Trx) domain was found to be close to the core SNP and specifically expressed in buds and branches of weeping mei. Co-expression analysis of Pm024213 showed that most of the related genes were involved in auxin and lignin biosynthesis. These findings provide insights into the regulatory mechanism of the weeping trait and effective molecular markers for molecular-assisted breeding in Prunus mume.


DNA Research ◽  
2019 ◽  
Vol 26 (5) ◽  
pp. 399-409 ◽  
Author(s):  
Rumi Sasai ◽  
Hiroaki Tabuchi ◽  
Kenta Shirasawa ◽  
Kazuki Kishimoto ◽  
Shusei Sato ◽  
...  

Abstract The southern root-knot nematode, Meloidogyne incognita, is a pest that decreases yield and the quality of sweetpotato [Ipomoea batatas (L.) Lam.]. There is a demand to produce resistant cultivars and develop DNA markers to select this trait. However, sweetpotato is hexaploid, highly heterozygous, and has an enormous genome (∼3 Gb), which makes genetic linkage analysis difficult. In this study, a high-density linkage map was constructed based on retrotransposon insertion polymorphism, simple sequence repeat, and single nucleotide polymorphism markers. The markers were developed using F1 progeny between J-Red, which exhibits resistance to multiple races of M. incognita, and Choshu, which is susceptible to multiple races of such pest. Quantitative trait locus (QTL) analysis and a genome-wide association study detected highly effective QTLs for resistance against three races, namely, SP1, SP4, and SP6-1, in the Ib01-6 J-Red linkage group. A polymerase chain reaction marker that can identify genotypes based on single nucleotide polymorphisms located in this QTL region can discriminate resistance from susceptibility in the F1 progeny at a rate of 70%. Thus, this marker could be helpful in selecting sweetpotato cultivars that are resistant to multiple races of M. incognita.


Insects ◽  
2021 ◽  
Vol 12 (9) ◽  
pp. 836
Author(s):  
Longqing Shi ◽  
Meng Dong ◽  
Ling Lian ◽  
Junian Zhang ◽  
Yongsheng Zhu ◽  
...  

The brown planthopper (BPH) is one of the main pests endangering rice yields. The development of rice varieties harboring resistance genes is the most economical and effective method of managing BPH. To identify new BPH resistance-related genes, a total of 123 rice varieties were assessed for resistance and durable resistance. Three varieties were immune, and nine were highly resistant to BPH. After whole-genome resequencing of all 123 varieties, 1,897,845 single nucleotide polymorphisms (SNPs) were identified. Linkage disequilibrium (LD) decay analysis showed that the average LD of the SNPs at 20 kb was 0.30 (r2) and attenuated to half value (~0.30) at a distance of about 233 kb. A genome-wide association study (GWAS) of durable resistance to BPH was conducted using the Fast-MLM model. One quantitative trait locus, identified on chromosome 2, included 13 candidate genes. Two candidate genes contained a leucine-rich repeat and CC-NBS-LRR or NB-ARC domains, which might confer resistance to pests or diseases. Interestingly, LOC_Os02g27540 was highly expressed and was induced by BPH; GWAS identified potential rice genes coding for durable resistance to BPH. This study helps to elucidate the mechanism of durable resistance to BPH in rice and provides essential genetic information for breeding and functional verification of resistant varieties.


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