Novel resistance mechanism of barley chlorina f104 antenna mutant against photoinhibition: possible role of new identified chloroplastic cpNrp protein

Optimizing the antenna size by reducing the chlorophyll (Chl) content is an effective strategy to improve solar energy conversion efficiencies in dense crop monocultures. To elucidate the physiological and molecular mechanisms that regulate Chl biosynthesis and understand the effects of lower Chl content on the photosynthetic process, a light-intensity-dependent yellow-green wheat mutant (Jimai5265yg) was characterized to determine its morphological, histological, physiological, and transcriptional differences with wild type. In addition to lower Chl content with a higher Chl a/b ratio, Jimai5265yg has spherical chloroplasts with few plastoglobule. It is counterintuitive that the photochemical quantum yield of both photosystem I and photosystem II and the following CO assimilation rate significantly increased, but the value of nonphotochemical quenching decreased, indicating a reduction of the photoprotective capacity of this yellow-green mutant. Analysis of intermediate pools and the expression of genes in the Chl synthesis pathway indicated that Mg-protoporphyrin IX (Mg-Proto IX) synthesis was partially blocked due to the imbalanced expression of Mg-chelatase subunits. Interestingly, the expression of photosynthesis-associated nuclear genes (PhANGs) was upregulated, resembling gun mutants which have defects in the Mg-Proto IX-mediated plastid-to-nucleus signaling pathway. A genetic analysis indicated that the yellow-green phenotype was controlled by two nuclear recessive genes located on chromosomes 4AL and 4BL. Jimai5265yg is a novel chlorina mutant which could be used for understanding photosynthesis improvement mechanisms.

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Rapid mapping of a chlorina mutant gene cn-A1 in hexaploid wheat by bulked segregant analysis and single nucleotide polymorphism genotyping arrays

Jiang

Wang

Jian

et al. 2019

Crop Pasture Sci.

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The yellow–green leaf mutant can be exploited in photosynthesis and plant development research. A Triticum aestivum mutant with the chlorina phenotype, here called B23, was produced by treatment with the chemical mutagen sodium azide. This B23 mutant showed significantly lower chlorophyll content than wild-type Saannong33, and its chloroplast structure was abnormal. All its yield-related traits, except for the number of spikes per plant, were also significantly decreased. Genetic analysis confirmed that the mutant phenotype was controlled by a recessive gene, here designated cn-A1. Using bulked segregant analysis and the wheat 660K single nucleotide polymorphism array, the cn-A1 gene was mapped to chromosome 7AL, and 11 polymorphic markers were developed. Further analysis showed that cn-A1 was located in a 1.1-cM genetic region flanked by Kompetitive allele specific PCR (KASP) markers 660K-7A12 and 660K-7A20, which corresponded to a physical interval of 3.48 Mb in T. aestivum cv. Chinese Spring chromosome 7AL containing 47 predicted genes with high confidence. These results are expected to accelerate the process of cloning the cn-A1 gene and facilitate understanding of the mechanisms underlying chlorophyll metabolism and chloroplast development in wheat.

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Novel resistance mechanism of barley chlorina f104 antenna mutant against photoinhibition: possible role of new identified chloroplastic cpNrp protein

Abstract: Protein with NmrA domain serving as the receptor for oxidized NAD

Cited by 3 publications

References 50 publications

Perspectives in High-Throughput Phenotyping of Qualitative Traits at the Whole-Plant Level

Perspectives in High-Throughput Phenotyping of Qualitative Traits at the Whole-Plant Level

Physiological and transcriptomic analyses of a yellow-green mutant with high photosynthetic efficiency in wheat (Triticum aestivum L.)

Rapid mapping of a chlorina mutant gene cn-A1 in hexaploid wheat by bulked segregant analysis and single nucleotide polymorphism genotyping arrays

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