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BẢN TIN THỨ TƯ 27-7-2022
BẢN TIN THỨ TƯ 27-7-2022
Bản tin số 1

Researchers Discover Gene that Helps Maize Adapt to High Elevations and Cold Temperatures

North Carolina State University researchers have shown that the maize gene HPC1 modulates certain chemical processes that contribute to flowering time, and originated from “teosinte mexicana,” a precursor to modern-day corn that grows wild in the highlands of Mexico.
Maize grown in higher altitudes, like the highlands of Mexico, needs special accommodations to grow successfully. Colder temperatures in mountainous regions put maize at a slight disadvantage compared with maize grown at lower elevations and higher temperatures. At high elevations and colder temperatures, maize needs to accumulate heat, taking three times longer to grow than at lower elevations. In corn grown in low elevations, the HPC1 gene breaks down phospholipids that in other species have been shown to bind to important proteins that accelerate flowering time. In higher elevations, though, the gene misfires, but to the benefit of highland maize.
HPC1 breaks down phospholipids that in other species have been shown to bind to important proteins that accelerate flowering time. The research team used CRISPR-Cas9 to develop a mutant and confirmed the metabolic function of HPC1. In the paper published in the Proceedings of the National Academy of Sciences, the researchers showed results of vast experiments throughout the lowlands and highlands in Mexico, where the highland version of the gene was present. They found that maize with the highlands version of the gene flowered one day earlier than plants without the gene. Meanwhile, maize grown in the lowlands with the highlands version of the gene flowered one day later than plants without that gene version.
For more details about this study, read the news article in NC State University News.
 
 
Bản tin số 2

Scientists Discover Critical Immune Component in Barley

Many valuable cereal crops come from the same grass family, Poaceae, including barley, wheatrice, and maize. Scientists have been working to better understand the molecular mechanisms behind this lineage's survival to ensure that these plants continue to flourish and feed the world in years to come.
Grasses have evolved into the thriving varieties they are today while diseases that infect them evolved alongside them. The Pucciniales, an order of fungal pathogens that cause rust diseases includes stripe rust, Puccinia striiformis, which is present in all major wheat-growing areas of the world.
P. striiformis is an adaptable pathogen. However, while wheat stripe rust has been endemic in Australia for more than 60 years, it has not adapted to infect barley despite both crops being grown in the same regions, and the source of this resistance has remained unclear. The Matthew Moscou group at The Sainsbury Laboratory (TSL) identified three resistance (R) gene loci designated Rps6, Rps7, and Rps8, contributing to barley's non-adapted resistance to wheat stripe rust. To better understand the role of these R genes in barley, the group fine-mapped Rps8 to a region on chromosome 4H, which encompasses a presence/absence variation across diverse barley accessions, and found that Rps8-mediated resistance to wheat stripe rust is conferred by a receptor kinase (Pur1) and a Poales-specific Exo70 (Exo70FX12). The group says this is an exciting discovery in plant immunity and cereal evolution. This information will allow scientists to transfer wheat stripe rust immunity traits to another variety.
For more details, read the news article on the TSL website.
 
BẢN TIN KHOA HỌC

A GWAS identified a major QTL for resistance to Fusarium wilt (Fusarium oxysporum f. sp. vasinfectum) race 4 in a MAGIC population of Upland cotton and a meta-analysis of QTLs for Fusarium wilt resistance

Theoretical and Applied Genetics July 2022; vol. 135: 2297–2312

Key message

A major QTL conferring resistance to Fusarium wilt race 4 in a narrow region of chromosome D02 was identified in a MAGIC population of 550 RILs of Upland cotton.

Abstract

Numerous studies have been conducted to investigate the genetic basis of Fusarium wilt (FW, caused by Fusarium oxysporum f. sp. vasinfectum, FOV) resistance using bi-parental and association mapping populations in cotton. In this study, a multi-parent advanced generation inter-cross (MAGIC) population of 550 recombinant inbred lines (RILs), together with their 11 Upland cotton (Gossypium hirsutum) parents, was used to identify QTLs for FOV race 4 (FOV4) resistance. Among the parents, Acala Ultima, M-240 RNR, and Stoneville 474 were the most resistant, while Deltapine Acala 90, Coker 315, and Stoneville 825 were the most susceptible. Twenty-two MAGIC lines were consistently resistant to FOV4. Through a genome-wide association study (GWAS) based on 473,516 polymorphic SNPs, a major FOV4 resistance QTL within a narrow region on chromosomes D02 was detected, allowing identification of 14 candidate genes. Additionally, a meta-analysis of 133 published FW resistance QTLs showed a D subgenome and individual chromosome bias and no correlation between homeologous chromosome pairs. This study represents the first GWAS study using a largest genetic population and the most comprehensive meta-analysis for FW resistance in cotton. The results illustrated that 550 lines were not enough for high resolution mapping to pinpoint a candidate gene, and experimental errors in phenotyping cotton for FW resistance further compromised the accuracy and precision in QTL localization and identification of candidate genes. This study identified FOV4-resistant parents and MAGIC lines, and the first major QTL for FOV4 resistance in Upland cotton, providing useful information for developing FOV4-resistant cultivars and further genomic studies towards identification of causal genes for FOV4 resistance in cotton.
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