scholarly journals Arpa Nikotinamin Sentaz1 (HvNAS1) Genini Yüksek Seviyede İfade Eden Arabidopsis thaliana Bitkileri Demir Eksikliğine Dayanıklılık Gösterir

Author(s):  
Emre Aksoy ◽  
Amir Maqbool ◽  
Buasimuhan Abudureyimu

Iron (Fe) is an important trace mineral for plant development, and plants grown in Fe deficiency experience yield losses due to the leaf chlorosis. In addition to agronomic measures that can be taken to minimize these losses, new plant genotypes can be developed effectively through genetic engineering. While dicots such as Arabidopsis thaliana use a reduction-based strategy to uptake high amounts of iron from the rhizosphere, the chelation strategy has evolved in Gramineous plants including barley (Hordeum vulgare). In this study, barley NICOTIANAMINE SYNTHASE1 (HvNAS1) gene, which is responsible for the production of nicotianamine that can complex with iron, was cloned and expressed at a constitutive high level in Arabidopsis plants. The expression levels of Arabidopsis genes encoding for the proteins involved in iron uptake increased together with HvNAS1 in the T3 Arabidopsis plants. Moreover, the root lengths, root and stem fresh weights, ferric chelate reductase enzyme activities of the plants also increased in the transgenic Arabidopsis plants under Fe deficiency. In addition, significant increases in iron and zinc levels were determined in the roots and shoots of transgenic Arabidopsis plants. As a result, transgenic Arabidopsis plants overexpressing the barley HvNAS1 gene can take up more iron from the rhizosphere and carry this iron to the shoots. This study demonstrates the power of genetic engineering to develop Arabidopsis plants overexpressing the HvNAS1 gene and therefore tolerate iron deficiency.

Genetics ◽  
2001 ◽  
Vol 159 (4) ◽  
pp. 1765-1778
Author(s):  
Gregory J Budziszewski ◽  
Sharon Potter Lewis ◽  
Lyn Wegrich Glover ◽  
Jennifer Reineke ◽  
Gary Jones ◽  
...  

Abstract We have undertaken a large-scale genetic screen to identify genes with a seedling-lethal mutant phenotype. From screening ~38,000 insertional mutant lines, we identified >500 seedling-lethal mutants, completed cosegregation analysis of the insertion and the lethal phenotype for >200 mutants, molecularly characterized 54 mutants, and provided a detailed description for 22 of them. Most of the seedling-lethal mutants seem to affect chloroplast function because they display altered pigmentation and affect genes encoding proteins predicted to have chloroplast localization. Although a high level of functional redundancy in Arabidopsis might be expected because 65% of genes are members of gene families, we found that 41% of the essential genes found in this study are members of Arabidopsis gene families. In addition, we isolated several interesting classes of mutants and genes. We found three mutants in the recently discovered nonmevalonate isoprenoid biosynthetic pathway and mutants disrupting genes similar to Tic40 and tatC, which are likely to be involved in chloroplast protein translocation. Finally, we directly compared T-DNA and Ac/Ds transposon mutagenesis methods in Arabidopsis on a genome scale. In each population, we found only about one-third of the insertion mutations cosegregated with a mutant phenotype.


2019 ◽  
Vol 11 (3) ◽  
pp. 954-969 ◽  
Author(s):  
Yann Dussert ◽  
Isabelle D Mazet ◽  
Carole Couture ◽  
Jérôme Gouzy ◽  
Marie-Christine Piron ◽  
...  

Abstract Downy mildews are obligate biotrophic oomycete pathogens that cause devastating plant diseases on economically important crops. Plasmopara viticola is the causal agent of grapevine downy mildew, a major disease in vineyards worldwide. We sequenced the genome of Pl. viticola with PacBio long reads and obtained a new 92.94 Mb assembly with high contiguity (359 scaffolds for a N50 of 706.5 kb) due to a better resolution of repeat regions. This assembly presented a high level of gene completeness, recovering 1,592 genes encoding secreted proteins involved in plant–pathogen interactions. Plasmopara viticola had a two-speed genome architecture, with secreted protein-encoding genes preferentially located in gene-sparse, repeat-rich regions and evolving rapidly, as indicated by pairwise dN/dS values. We also used short reads to assemble the genome of Plasmopara muralis, a closely related species infecting grape ivy (Parthenocissus tricuspidata). The lineage-specific proteins identified by comparative genomics analysis included a large proportion of RxLR cytoplasmic effectors and, more generally, genes with high dN/dS values. We identified 270 candidate genes under positive selection, including several genes encoding transporters and components of the RNA machinery potentially involved in host specialization. Finally, the Pl. viticola genome assembly generated here will allow the development of robust population genomics approaches for investigating the mechanisms involved in adaptation to biotic and abiotic selective pressures in this species.


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