scholarly journals The Gametic Non-Lethal Gene Gal on Chromosome 5 Is Indispensable for the Transmission of the Co-Induced Semidwarfing Gene d60 in Rice

Biology ◽  
2019 ◽  
Vol 8 (4) ◽  
pp. 94
Author(s):  
Motonori Tomita ◽  
Takatoshi Tanisaka

The gametic lethal gene gal in combination with the semidwarfing gene d60 causes complementary lethality in rice. Here, we attempted to ascertain the existence of gal and clarify male gamete abortion caused by d60 and gal. Through the F2 to F4 generations derived from the cross between D60gal-homozygous and d60Gal-homozygous, progenies of the partial sterile plants (D60d60Galgal) were segregated in a ratio of 1 semidwarf (1 d60d60GalGal):2 tall and quarter sterile (2 D60d60Galgal):6 tall (2 D60d60GalGal:1 D60D60GalGal:2 D60D60Galgal:1 D60D60galgal), which is skewed from the Mendelian ratio of 1 semidwarf:3 tall. However, the F4 generation was derived from fertile and tall heterozygous F2 plants (D60d60GalGal), which were segregated in the Mendelian ratio of 1[semidwarf (d60d60GalGal)]:2[1 semidwarf:3 tall (D60d60GalGal)]:1[tall (D60D60GalGal)]. The backcrossing of D60Gal-homozygous tall F4 plants with Hokuriku 100 resulted in fertile BCF1 and BCF2 segregated in a ratio of 1 semidwarf:3 tall, proving that d60 is inherited as a single recessive gene in the D60d60GalGal genetic background (i.e., in the absence of gal). Further, gal was localized on chromosome 5, which is evident from the deviated segregation of d1 as 1:8 and linkage with simple sequence repeat (SSR) markers. Next-generation sequencing identified the candidate SNP responsible for Gal. In F1 and sterile F2, at the binucleate stage, partial pollen discontinued development. Degraded pollen lost vegetative nuclei, but second pollen mitosis raising two generative nuclei was observed. Thus, our study describes a novel genetic model for a reproductive barrier. This is the first report on such a complementary lethal gene, whose mutation allows the transmission of a co-induced valuable semidwarfing gene d60.

2000 ◽  
Vol 125 (3) ◽  
pp. 340-343 ◽  
Author(s):  
Mark J. Bassett ◽  
Kirk Hartel ◽  
Phil McClean

Inheritance of Anasazi pattern of partly colored seedcoats in common bean (Phaseolus vulgaris L.) was studied in a genetic stock t ana B V Anasazi BC3 5-593, whose Anasazi pattern is derived from Plant Introduction (PI) 451802. Line 5-593 is a determinate, Florida dry bean breeding line (with small black seeds) used as the recurrent parent in the development of many genetic stocks. The F2 from the cross t ana B V Anasazi BC3 5-593 × t z virgarcus BC3 5-593 segregated for two nonparental phenotypic classes and was consistent with the hypothesis that a single recessive gene, with tentative symbol ana, produces the Anasazi pattern with t Z ana and a new partly colored pattern Anabip with t z ana. Thus, the Anasazi factor is not an allele at the Z locus. Analysis of 57 random F3 progenies from the cross t ana B V Anasazi BC3 5-593 × t z virgarcus BC3 5-593 supported a genetic model where: 1) with t Z the Anasazi phenotype is controlled by a single recessive gene ana, i.e., genotype t Z ana, 2) the Anabip phenotype has the genotype t z ana, and 3) t Z/z ana produces a restricted Anasazi pattern. The allelism test cross t z ana Anabip BC3 5-593 × t z lers white BC3 5-593 produced complementation in the F2, demonstrating nonallelism of Ana (actually Bip) with the L locus. The allelism test cross t z ana Anabip BC3 5-593 × t z bip bipunctata BC3 5-593 failed to show complementation in F1 and F2, demonstrating allelism of Ana with the Bip locus. Using bulk segregant analysis, molecular markers linked in coupling to the Ana (OM9200, 5.4 cM) and Bip (OJ17700, 6.0 cM) genes were discovered. Allelism was also suggested by the result that the same linkage distance and recombination pattern were observed when the Ana marker was used to score the bipunctata population. We propose the gene symbol bipana for the recessive allele at the Bip locus that produces Anasazi pattern with genotype t Z bipana and the Anabip pattern with genotype t z bipana. Although bipana and bip are both recessive to Bip, their interactions with the Z locus are extraordinarily different. The pattern restrictive power of bipana expresses partly colored pattern with t Z, whereas bip requires t z to express partly colored pattern.


Author(s):  
Gangjun Zhao ◽  
Caixia Luo ◽  
Jianning Luo ◽  
Junxing Li ◽  
Hao Gong ◽  
...  

Abstract Key message A dwarfism gene LacDWARF1 was mapped by combined BSA-Seq and comparative genomics analyses to a 65.4 kb physical genomic region on chromosome 05. Abstract Dwarf architecture is one of the most important traits utilized in Cucurbitaceae breeding because it saves labor and increases the harvest index. To our knowledge, there has been no prior research about dwarfism in the sponge gourd. This study reports the first dwarf mutant WJ209 with a decrease in cell size and internodes. A genetic analysis revealed that the mutant phenotype was controlled by a single recessive gene, which is designated Lacdwarf1 (Lacd1). Combined with bulked segregate analysis and next-generation sequencing, we quickly mapped a 65.4 kb region on chromosome 5 using F2 segregation population with InDel and SNP polymorphism markers. Gene annotation revealed that Lac05g019500 encodes a gibberellin 3β-hydroxylase (GA3ox) that functions as the most likely candidate gene for Lacd1. DNA sequence analysis showed that there is an approximately 4 kb insertion in the first intron of Lac05g019500 in WJ209. Lac05g019500 is transcribed incorrectly in the dwarf mutant owing to the presence of the insertion. Moreover, the bioactive GAs decreased significantly in WJ209, and the dwarf phenotype could be restored by exogenous GA3 treatment, indicating that WJ209 is a GA-deficient mutant. All these results support the conclusion that Lac05g019500 is the Lacd1 gene. In addition, RNA-Seq revealed that many genes, including those related to plant hormones, cellular process, cell wall, membrane and response to stress, were significantly altered in WJ209 compared with the wild type. This study will aid in the use of molecular marker-assisted breeding in the dwarf sponge gourd.


2000 ◽  
Vol 125 (2) ◽  
pp. 217-221 ◽  
Author(s):  
Jose Lopez-Medina ◽  
James N. Moore ◽  
Ronald W. McNew

Inheritance of the primocane-fruiting (PF) characteristic was studied in seedling populations of tetraploid (4x) blackberries (Rubus subgenus Rubus). Four selections (A-1836, A-593, A-830, and A-1680) and two cultivars (`Arapaho' and `Shawnee') were used as parents in a full diallel crossing scheme. Selection A-593 was used as the main source for PF due to its origin (`Brazos' × `Hillquist,' the latter an old PF cultivar). All parents except `Shawnee' have A-593 in their parentage; among the parents, only A-1836 fully expresses PF. Selfing of A-1836 resulted in 100% PF offspring, indicating that A-1836 is homozygous for this trait. Selfing of A-593, A-830, and `Arapaho' produced either a 35:1 or a 20.8:1 FF (floricane or summer-fruiting):PF segregation ratio, fitting a tetrasomic inheritance model under either random chromosome assortment (RCSA) or random chromatid assortment (RCTA), respectively, also suggesting that PF is controlled by a single recessive gene and that the parents are duplex (AAaa) for this trait. Selection A-1680 and `Shawnee' selfed did not produce PF progeny, but when crossed with the nulliplex A-1836, gave a 27:1 FF:PF ratio, indicating RCTA and that they are triplex (AAAa) for PF. According to these research, both gametic outputs (RCSA and RCTA) seem to operate in 4x blackberry. The intensity in expression of PF had a negative relationship with time to harvest, with those seedlings showing the highest PF scores producing a crop in early to mid-August. This knowledge will be helpful in implementing breeding strategies to produce PF blackberry cultivars.


Plants ◽  
2020 ◽  
Vol 9 (8) ◽  
pp. 965 ◽  
Author(s):  
Xian-Lin Guo ◽  
Hong-Yi Zheng ◽  
Megan Price ◽  
Song-Dong Zhou ◽  
Xing-Jin He

Chamaesium H. Wolff (Apiaceae, Apioideae) is a small genus mainly distributed in the Hengduan Mountains and the Himalayas. Ten species of Chamaesium have been described and nine species are distributed in China. Recent advances in molecular phylogenetics have revolutionized our understanding of Chinese Chamaesium taxonomy and evolution. However, an accurate phylogenetic relationship in Chamaesium based on the second-generation sequencing technology remains poorly understood. Here, we newly assembled nine plastid genomes from the nine Chinese Chamaesium species and combined these genomes with eight other species from five genera to perform a phylogenic analysis by maximum likelihood (ML) using the complete plastid genome and analyzed genome structure, GC content, species pairwise Ka/Ks ratios and the simple sequence repeat (SSR) component. We found that the nine species’ plastid genomes ranged from 152,703 bp (C. thalictrifolium) to 155,712 bp (C. mallaeanum), and contained 133 genes, 34 SSR types and 585 SSR loci. We also found 20,953–21,115 codons from 53 coding sequence (CDS) regions, 38.4–38.7% GC content of the total genome and low Ka/Ks (0.27–0.43) ratios of 53 aligned CDS. These results will facilitate our further understanding of the evolution of the genus Chamaesium.


Genome ◽  
1988 ◽  
Vol 30 (2) ◽  
pp. 229-233 ◽  
Author(s):  
C. F. Konzak ◽  
L. R. Joppa

The durum wheat (Triticum turgidum L. var. durum) cultivar 'Vic' was treated with the chemical mutagen N-methyl-N′-nitrosourea and among the M2 progeny a mutant with "chocolate chaff" (designated cc) was identified. Genetic analyses indicated that chocolate chaff is due to a single recessive gene mutation. The penetrance of the gene for chocolate chaff was environmentally influenced and varied from dark blotches on the glumes to complete coloration of culms as well as spikes. To determine the chromosomal location of the gene, the mutant was crossed with a set of 'Langdon' durum disomic substitution lines in which each of the 14 A- and B-genome chromosomes of durum wheat were replaced by their respective D-genome homoeologues. The segregation of cc was normal in all of the crosses except for those with the 7D(7A) and 7D(7B) lines. Cytogenetic analysis indicated that the gene was located on chromosome 7B, and that chromosome 7D has a gene that prevents the expression of cc when present in one or more copies. It was shown that the 'Langdon' D-genome disomic substitution lines can be used to determine the chromosomal location of genes in tetraploid wheat.Key words: Triticum turgidum, aneuploid, chromosome substitution, monosomic, cytogenetics.


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