scholarly journals Meiotic behavior of economically important plant species: the relationship between fertility and male sterility

2000 ◽  
Vol 23 (4) ◽  
pp. 997-1002 ◽  
Author(s):  
Maria Suely Pagliarini

Meiosis is an event of high evolutionary stability which culminates in a reduction of chromosome number. The normal and harmonious course of meiosis ensures gamete viability. The cytologic events of gametogenesis are controlled by a large number of genes that act from premeiotic to postmeiotic mitosis. Mutations in these genes cause anomalies that may impair fertility, and many abnormalities affecting plant fertility or causing total male sterility have been detected during the evaluation of meiotic behavior in some species. Some of these abnormalities have been frequently described in the literature, while others have not been previously reported. The most frequent abnormalities found in the species analyzed were irregular chromosome segregation, cytomixis, chromosome stickiness, mixoploidy, chromosome fragmentation, syncyte formation, abnormal spindles, and failure of cytokinesis. Uncommon abnormalities, such as chromosome elimination during microsporogenesis, were found in one species. Original meiotic mutations affecting different steps of meiosis were also observed in these species, especially in maize, Paspalum and soybean. Some mutants present characteristics that may be exploited successfully in breeding programs because they cause total male sterility.

Genetics ◽  
1998 ◽  
Vol 149 (1) ◽  
pp. 143-155 ◽  
Author(s):  
Bruce D McKee ◽  
Kathy Wilhelm ◽  
Cynthia Merrill ◽  
Xiao-jia Ren

Abstract In Drosophila melanogaster, deletions of the pericentromeric X heterochromatin cause X-Y nondisjunction, reduced male fertility and distorted sperm recovery ratios (meiotic drive) in combination with a normal Y chromosome and interact with Y-autosome translocations (T(Y;A)) to cause complete male sterility. The pericentromeric heterochromatin has been shown to contain the male-specific X-Y meiotic pairing sites, which consist mostly of a 240-bp repeated sequence in the intergenic spacers (IGS) of the rDNA repeats. The experiments in this paper address the relationship between X-Y pairing failure and the meiotic drive and sterility effects of Xh deletions. X-linked insertions either of complete rDNA repeats or of rDNA fragments that contain the IGS were found to suppress X-Y nondisjunction and meiotic drive in Xh−/Y males, and to restore fertility to Xh−/T(Y;A) males for eight of nine tested Y-autosome translocations. rDNA fragments devoid of IGS repeats proved incapable of suppressing either meiotic drive or chromosomal sterility. These results indicate that the various spermatogenic disruptions associated with X heterochromatic deletions are all consequences of X-Y pairing failure. We interpret these findings in terms of a novel model in which misalignment of chromosomes triggers a checkpoint that acts by disabling the spermatids that derive from affected spermatocytes.


Genetics ◽  
1991 ◽  
Vol 129 (3) ◽  
pp. 885-895
Author(s):  
O Folkerts ◽  
M R Hanson

Abstract A mitochondrial DNA (mtDNA) region termed the S-pcf locus has previously been correlated with cytoplasmic male sterility (CMS) in Petunia. In order to understand the relationship of the S-pcf locus to homologous sequences found elsewhere in mtDNAs of both CMS and fertile lines, the structure of the mitochondrial genome of CMS Petunia line 3688 was determined by cosmid walking. The S-pcf locus, which includes the only copies of genes for NADH dehydrogenase subunit 3 (nad3) and small ribosomal subunit protein 12 (rps12) was found to be located on a circular map of 396 kb, while a second almost identical circular map of 407 kb carries the only copies of the genes for 18S and 5S rRNA (rrn18 and rrn5), the only copy of a conserved unidentified gene (orf25), and the only known functional copy of atp9. Three different copies of a recombination repeat were found in six genomic environments, predicting sub-genomic circles of 277, 266 and 130 kb. The ratio of atp9 to S-pcf mtDNA sequences was approximately 1.5 to 1, indicating that sub-genomic molecules carrying these genes differ in abundance. Comparison of the mtDNA organization of the CMS line with that of the master circle of fertile Petunia line 3704 reveals numerous changes in order and orientation of ten different sectors.


2017 ◽  
Vol 3 (1) ◽  
pp. 1-5
Author(s):  
Futoshi Ishiguri ◽  
Kazuko Makino ◽  
Imam Wahyudi ◽  
Jun Tanabe ◽  
Yuya Takashima ◽  
...  

The present study clarified the relationship between the growth and wood properties of 54-year-old Agathis sp. trees planted in Indonesia. Stem diameter, pilodyn penetration, and stress-wave velocity (SWV) were measured for all trees (35 trees) in a plot (30  30 m) located almost at the center of a stand. Based on the mean stem diameter, 10 standard trees in a plot were selected for measuring the basic density (BD) and compressive strength parallel to grain (CS). Core samples (5 mm in diameter) were collected from the 10 selected trees to determine BD and CS. The mean stem diameter, pilodyn penetration and SWV in the plot were 40.2  11.3 cm, 23.4  2.1 cm, and 3.85  0.43 km/s, respectively. No  significant correlation coefficeint (r = -0.327, no significance at 5% level) was obtained between stem diameter and SWV. The mean BD and CS in the 10 trees were 0.42  0.03 g/cm3  and 28.1  2.7 MPa, respectively. A significant positive  correlation was observed between BD and CS. Analysis of variance (ANOVA) revealed a significant difference between BD and CS values of the 10 trees, indicating that wood properties may differ among trees with the same standard growth in a stand. From these results, we concluded that wood quality improvement in this species could be achieved by selecting  trees with high density and strength in tree breeding programs.


2020 ◽  
Author(s):  
Yanping Tan ◽  
Tong Chen ◽  
Ze Tian ◽  
Jiayang Li ◽  
Xuequn Liu ◽  
...  

Abstract The identification and development of new cytoplasmic male sterility (CMS) lines in higher plants is important for the preservation of grain security and the prevention of homogenization of hybrid rice. Molecular markers assisted selection (MAS) based on CMS-associated genes or mitochondrial-specific chimeric sequences are important for rapid and effective breeding of new CMS lines and hybrids. In our study, the distribution and allele variation of orfH79 and orf290 genes were characterized from 273 wild and cultivated rice in the AA genome species. Based on the alignment of nucleotide and amino acid sequences, four accessions with orfH79 and three accessions with orf290 were screened. Four novel CMS lines carrying orfH79 haplotypes and three novel CMS lines carrying orf290 haplotypes were then developed using multiple backcross generations with a maintainer line under MAS. The breeding process used in our study provides an efficient and feasible approach for selecting new CMS lines. CMS lines selected in our study are important for enriching rice germplasm resources and guaranteeing rice breeding programs.


Plant Disease ◽  
2022 ◽  
Author(s):  
Francisco Beluzán ◽  
Xavier Miarnau ◽  
Laura Torguet ◽  
Lourdes Zazurca ◽  
Paloma Abad-Campos ◽  
...  

Twenty-five almond cultivars were assessed for susceptibility to Diaporthe amygdali, causal agent of twig canker and shoot blight disease. In laboratory experiments, growing twigs were inoculated with four D. amygdali isolates. Moreover, growing shoots of almond cultivars grafted onto INRA ‘GF-677’ rootstock were used in four-year field inoculations with one D. amygdali isolate. In both type of experiments, inoculum consisted of agar plugs with mycelium, which were inserted underneath the bark and the lesion lengths caused by the fungus were measured. Necrotic lesions were observed in the inoculated almond cultivars both in laboratory and field tests, confirming the susceptibility of all the evaluated cultivars to all the inoculated isolates of D. amygdali. Cultivars were grouped as susceptible or very susceptible according to a cluster analysis. The relationship between some agronomic traits and cultivar susceptibility was also investigated. Blooming and ripening times were found relevant variables to explain cultivars performance related to D. amygdali susceptibility. Late and very late blooming, and early and medium ripening cultivars were highly susceptible to D. amygdali. Our results may provide valuable information that could assist in ongoing breeding programs of this crop and additionally in the selection of cultivars for new almond plantations.


2020 ◽  
Vol 100 (3) ◽  
pp. 455-461
Author(s):  
Yifan Liu ◽  
Yunjie Tu ◽  
Ming Zhang ◽  
Jianmin Zou ◽  
Gaige Ji ◽  
...  

The comb is an important secondary sexual characteristic and comb growth traits, such as size and color of the comb, are widely used as indicators in chicken breeding programs. However, the genetic basis for these traits remains mostly unknown. It was found that the chondroadherin-like (CHADL) gene was up-regulated in large combs and was located in reported comb growth quantitative trait loci. In this study, tissue-specific expressions, expression patterns in combs of different ages, and CHADL polymorphisms were analyzed to investigate the relationship between this gene and comb growth traits of Partridge Shank roosters. The results showed that CHADL was more highly expressed in combs than in 10 other tissues, and its expressions in combs tended to gradually increase from the 5-wk-old mark to the 26-wk-old mark. The single-nucleotide polymorphism rs316423539 in the CHADL gene was significantly associated with the comb area and height, whereas rs14822286 was highly correlated with the comb color. Moreover, H1H5, H1H6, and H3H6 were the most advantageous genotype combinations for comb growth traits. Our results might help understand the molecular mechanism of comb growth traits and improve these traits directly by marker assistant selections.


Plants ◽  
2020 ◽  
Vol 9 (6) ◽  
pp. 773
Author(s):  
Kimberly Vanous ◽  
Thomas Lübberstedt ◽  
Rania Ibrahim ◽  
Ursula K. Frei

Doubled haploid technology is highly successful in maize breeding programs and is contingent on the ability of maize inducers to efficiently produce haploids. Knowledge of the genes involved in haploid induction is important for not only developing better maize inducers, but also to create inducers in other crops. The main quantitative trait loci involved in maize haploid induction are qhir1 and qhir8. The gene underlying qhir1 has been discovered and validated by independent research groups. Prior to initiation of this study, the gene associated with qhir8 had yet to be recognized. Therefore, this research focused on characterizing positional candidate genes underlying qhir8. Pursuing this goal, a strong candidate for qhir8, GRMZM2G435294 (MYO), was silenced by RNAi. Analysis of crosses with these heterozygous RNAi-transgenic lines for haploid induction rate revealed that the silencing of MYO significantly enhanced haploid induction rate by an average of 0.6% in the presence of qhir1. Recently, GRMZM2G465053 (ZmDMP) was identified by map-based gene isolation and shown to be responsible for qhir8. While our results suggest that MYO may contribute to haploid induction rate, results were inconsistent and only showing minor increases in haploid induction rate compared to ZmDMP. Instead, reciprocal crosses clearly revealed that the silencing of MYO causes male sterility.


1982 ◽  
Vol 40 (2) ◽  
pp. 165-174 ◽  
Author(s):  
Prasad R. K. Koduru ◽  
T. G. K. Murthy ◽  
K. V. Lakshmi ◽  
M. Krishna Rao

SUMMARYThe relationship between chromosome pairing and chromosome fragmentation has been studied in a gene controlled mutant of pearl millet (2n = 14). Premeiotic mitosis, premeiotic cell development and early prophase I are normal without any fragments, which first appear at pachytene. The extent of fragmentation varies from zero to very extreme with two discrete classes of plants, namely those with partial fragmentation and those with multiple fragmentation. A quantitative analysis of bivalent distribution and the distribution of AI bridges in desynaptic and fragmented cells show all of them to be nonrandom events. We suggest that in cells showing partial fragmentation the bridges and fragments result from U-type exchanges at pachytene. The reduced frequency of AII bridges indicates relatively low sister chromatid reunion at pachytene. In multiple fragmented plants numerous minute fragments were seen from pachytene. Despite these anomalies most PMCs complete meiosis but subsequently abort at the pollen grain stage. The mutant gene also causes disturbances in the sequence of meiotic development in the ear and in the synchronous development of PMCs within an anther. It has no effect on the tapetum or on the physiological development of the anther.


1999 ◽  
Vol 146 (1) ◽  
pp. 13-28 ◽  
Author(s):  
Joydeep Basu ◽  
Hassan Bousbaa ◽  
Elsa Logarinho ◽  
ZeXiao Li ◽  
Byron C. Williams ◽  
...  

We have characterized the Drosophila mitotic checkpoint control protein Bub1 and obtained mutations in the bub1 gene. Drosophila Bub1 localizes strongly to the centromere/kinetochore of mitotic and meiotic chromosomes that have not yet reached the metaphase plate. Animals homozygous for P-element–induced, near-null mutations of bub1 die during late larval/pupal stages due to severe mitotic abnormalities indicative of a bypass of checkpoint function. These abnormalities include accelerated exit from metaphase and chromosome missegregation and fragmentation. Chromosome fragmentation possibly leads to the significantly elevated levels of apoptosis seen in mutants. We have also investigated the relationship between Bub1 and other kinetochore components. We show that Bub1 kinase activity is not required for phosphorylation of 3F3/2 epitopes at prophase/prometaphase, but is needed for 3F3/2 dephosphorylation at metaphase. Neither 3F3/2 dephosphorylation nor loss of Bub1 from the kinetochore is a prerequisite for anaphase entry. Bub1's localization to the kinetochore does not depend on the products of the genes zw10, rod, polo, or fizzy, indicating that the kinetochore is constructed from several independent subassemblies.


2001 ◽  
Vol 28 (1) ◽  
pp. 19-20 ◽  
Author(s):  
W. D. Branch

Abstract A better understanding of the genetic relationship among different testa colors is needed in peanut (Arachis hypogaea L.) breeding programs. Numerous genes are involved in this important U.S. market quality trait. However, the relationship among some of these genes is not yet known. The objective of this study was to determine the interaction among the three genes (P, w1, and w2) controlling purple and wine testa color. No maternal or cytoplasmic differences were found among three reciprocal purple x wine testcrosses. The F1, F2, and F3 segregation results suggest that purple testa color of PI 331334 differs from that of wine testa color parental lines (PI 264549, Wine-Frr 1 and Wine-Frr 2) by only two genes. These findings illustrate that the dominant purple testa color gene (P) is independent from at least one of the two recessive wine genes (w1 w1 or w2w2).


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