Limits...
Aberrant Meiotic Prophase I Leads to Genic Male Sterility in the Novel TE5A Mutant of Brassica napus

View Article: PubMed Central - PubMed

ABSTRACT

Genic male sterility (GMS) has already been extensively utilized for hybrid rapeseed production. TE5A is a novel thermo-sensitive dominant GMS line in Brassica napus, however, its mechanisms of GMS remain largely unclear. Histological and Transmission electron microscopy (TEM) analyses of anthers showed that the male gamete development of TE5A was arrested at meiosis prophase I. EdU uptake of S-phase meiocytes revealed that the TE5A mutant could accomplish DNA replication, however, chromosomal and fluorescence in situ hybridization (FISH) analyses of TE5A showed that homologous chromosomes could not pair, synapse, condense and form bivalents. We then analyzed the transcriptome differences between young floral buds of sterile plants and its near-isogenic fertile plants through RNA-Seq. A total of 3,841 differentially expressed genes (DEGs) were obtained, some of which were associated with homologous chromosome behavior and cell cycle control during meiosis. Dynamic expression changes of selected candidate DEGs were then analyzed at different anther developmental stages. The present study not only demonstrated that the TE5A mutant had defects in meiotic prophase I via detailed cytological analysis, but also provided a global insight into GMS-associated DEGs and elucidated the mechanisms of GMS in TE5A through RNA-Seq.

No MeSH data available.


Related in: MedlinePlus

Comparison of floral morphology between sterile and fertile plants.(A) young buds of sterile and fertile plants (left, fertile; right, sterile); (B) anthers corresponding to different lengths of young buds (0.5, 0.8, 1.0, 1.5, 2.0, and 4.0 mm; upper, sterile; down, fertile).
© Copyright Policy - open-access
Related In: Results  -  Collection

License
getmorefigures.php?uid=PMC5037387&req=5

f1: Comparison of floral morphology between sterile and fertile plants.(A) young buds of sterile and fertile plants (left, fertile; right, sterile); (B) anthers corresponding to different lengths of young buds (0.5, 0.8, 1.0, 1.5, 2.0, and 4.0 mm; upper, sterile; down, fertile).

Mentions: TE5A is a novel DGMS line that originated from a spontaneous mutant of the inbred line TE5. It exhibits ecotypic temperature sensitivity, it is fertile at low temperatures, and transforms to a completely sterile phenotype at temperatures of >20 °C during florescence. Therefore, the critical temperature controlling the fertility of TE5A was 20 °C. To acquire plants with the most similar genetic background, one heterozygous TE5A sterile plant was utilized as the female parent and crossed with the temporary maintainer GY12, resulting in an F1 population that presented fertility segregation. Sterile F1 plants were backcrossed to GY12 to produce the BC1 population. The BC3 population was then obtained by backcrossing sterile plants of the BC2 population with GY12. Its fertility was determined during flowering when the temperature was >20 °C. Sterile plants and fertile plants with a 1:1 fertility segregation ratio were derived from the BC3 population of the same genic background besides the sterile gene locus residing in sterile plants. At the same temperature (>20 °C), the fertile plants showed normal floral morphology and architecture, whereas sterile plants presented defective male floral organs (abnormal anthers, no pollen was produced, and stamens showing a reduction in size), and had normal flowers in other respects (Fig. 1A). During the early stages of stamen development, the sterile plants showed full and well developed stamens compared to that observed in the wild plants. Alterations were observed at the later stamen stage, stamens of fertile plants exhibited well-developed, yellow anthers, whereas sterile plants presented withered anthers with no pollen (Fig. 1B).


Aberrant Meiotic Prophase I Leads to Genic Male Sterility in the Novel TE5A Mutant of Brassica napus
Comparison of floral morphology between sterile and fertile plants.(A) young buds of sterile and fertile plants (left, fertile; right, sterile); (B) anthers corresponding to different lengths of young buds (0.5, 0.8, 1.0, 1.5, 2.0, and 4.0 mm; upper, sterile; down, fertile).
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC5037387&req=5

f1: Comparison of floral morphology between sterile and fertile plants.(A) young buds of sterile and fertile plants (left, fertile; right, sterile); (B) anthers corresponding to different lengths of young buds (0.5, 0.8, 1.0, 1.5, 2.0, and 4.0 mm; upper, sterile; down, fertile).
Mentions: TE5A is a novel DGMS line that originated from a spontaneous mutant of the inbred line TE5. It exhibits ecotypic temperature sensitivity, it is fertile at low temperatures, and transforms to a completely sterile phenotype at temperatures of >20 °C during florescence. Therefore, the critical temperature controlling the fertility of TE5A was 20 °C. To acquire plants with the most similar genetic background, one heterozygous TE5A sterile plant was utilized as the female parent and crossed with the temporary maintainer GY12, resulting in an F1 population that presented fertility segregation. Sterile F1 plants were backcrossed to GY12 to produce the BC1 population. The BC3 population was then obtained by backcrossing sterile plants of the BC2 population with GY12. Its fertility was determined during flowering when the temperature was >20 °C. Sterile plants and fertile plants with a 1:1 fertility segregation ratio were derived from the BC3 population of the same genic background besides the sterile gene locus residing in sterile plants. At the same temperature (>20 °C), the fertile plants showed normal floral morphology and architecture, whereas sterile plants presented defective male floral organs (abnormal anthers, no pollen was produced, and stamens showing a reduction in size), and had normal flowers in other respects (Fig. 1A). During the early stages of stamen development, the sterile plants showed full and well developed stamens compared to that observed in the wild plants. Alterations were observed at the later stamen stage, stamens of fertile plants exhibited well-developed, yellow anthers, whereas sterile plants presented withered anthers with no pollen (Fig. 1B).

View Article: PubMed Central - PubMed

ABSTRACT

Genic male sterility (GMS) has already been extensively utilized for hybrid rapeseed production. TE5A is a novel thermo-sensitive dominant GMS line in Brassica napus, however, its mechanisms of GMS remain largely unclear. Histological and Transmission electron microscopy (TEM) analyses of anthers showed that the male gamete development of TE5A was arrested at meiosis prophase I. EdU uptake of S-phase meiocytes revealed that the TE5A mutant could accomplish DNA replication, however, chromosomal and fluorescence in situ hybridization (FISH) analyses of TE5A showed that homologous chromosomes could not pair, synapse, condense and form bivalents. We then analyzed the transcriptome differences between young floral buds of sterile plants and its near-isogenic fertile plants through RNA-Seq. A total of 3,841 differentially expressed genes (DEGs) were obtained, some of which were associated with homologous chromosome behavior and cell cycle control during meiosis. Dynamic expression changes of selected candidate DEGs were then analyzed at different anther developmental stages. The present study not only demonstrated that the TE5A mutant had defects in meiotic prophase I via detailed cytological analysis, but also provided a global insight into GMS-associated DEGs and elucidated the mechanisms of GMS in TE5A through RNA-Seq.

No MeSH data available.


Related in: MedlinePlus