Diploid-tetraploid crosses as the instrument for obtaining apomictic maize plants

Tsvetova, M. I.; Elkonin, L. A.; Italianskaya, Y.

doi:10.3103/s106836741603023x

Cited by 3 publications

(1 citation statement)

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“…However, in these studies, maternal plants used in crosses derived from maize-Tripsacum hybrids. Previously, we have briefly described obtaining of diploid maternal-type plants in the progeny of diploid maize plants pollinated by tetraploid maize accessions [46]. In this paper, we present detailed description of our experiments on diploid-tetraploid crosses in maize, and present additional experimental data on interploid crosses in the grain sorghum lines, which suggest the existence of unreduced pseudogamous apomixis in these economically important crops.…”

Section: Introductionmentioning

confidence: 95%

Pseudogamous Apomixis in Maize and Sorghum in Diploid-Tetraploid Crosses

Tsvetova¹,

Lev²,

Italianskaya³

2019

Phyton

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Apomictic seed development is a complex process including formation of unreduced embryo sac, parthenogenetic embryo development from the egg cell, and endosperm formation either autonomously, or due to fertilization of polar nuclei by the sperm (under pseudogamous form of apomixis). In the latter case, an obstacle to the normal endosperm development is disturbance of maternal (m) -to-paternal (p) genomic ratio 2m: 1p that occurs in the cases of pollination of unreduced embryo sac with haploid sperms. Usage of tetraploid pollinators can overcome this problem because in such crosses maternal-to-paternal genomic ratio is 4m: 2p that provides formation of kernels with plump endosperm. Using tetraploid lines as pollen parents we observed formation of plump kernels on the ears and panicles of diploid maize and sorghum accessions. These kernels had hybrid endosperm and diploid maternaltype embryo or hybrid embryo with different ploidy level (2n, 3n, 4n). The frequencies of plump kernels on the ear ranged from 0.2-0.3% to 5.7-6.2% counting from the number of ovaries. Maternal-type plants were found in two maize lines, their frequency varying from 10.7 to 37.5% of the progeny plants. In CMS-lines of sorghum pollinated with tetraploid sorghum accessions, the frequency of plump kernels ranged from 0.6 to 14.0% counting from the number of ovaries; the frequency of maternal-type plants varied from 33.0 up to 96.1%. The hybrid nature of endosperm of the kernels that gave rise to maternal-type plants has been proved by marker gene expression and by SDS-electrophoresis of endosperm proteins. These data testify to variable modes of seed formation under diploid × tetraploid crosses in maize and sorghum both by amphi-and by apomixis. Therefore, usage of tetraploid pollinators might be a promising approach for isolation of apomixis in maize and sorghum accessions.

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Section: Introductionmentioning

confidence: 95%

Pseudogamous Apomixis in Maize and Sorghum in Diploid-Tetraploid Crosses

Tsvetova¹,

Lev²,

Italianskaya³

2019

Phyton

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Elimination of Chromosomes as a Mechanism for the Formation of Diploid Plants in Diploid–Tetraploid Crosses in Maize (Zea mays L.)

Elkonin,

Mavlyutova,

Kolesova

et al. 2023

Russ J Genet

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Elimination of Chromosomes as a Mechanism for the Formation of Diploid Plants in Diploid–Tetraploid Crosses in Maize (<i>Zea mays</i> L.)

Elkonin,

Mavlyutova,

Kolesova

et al. 2023

Genetika

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One of the main components of apomictic plant reproduction is the formation of unreduced embryo sacs (ESs). Heteroploid crosses, in which maternal diploid plants are pollinated by pollen of tetraploid paternal parent, can be used as an effective tool for identifying the ability to form unreduced ESs. In maize, in crosses 2n(♀) × 4n(♂), as a rule, shrunken kernels with a triploid embryo are formed, in which the development of the endosperm is impaired due to the deviation of the balance of the maternal (m) to paternal (p) genomes from the ratio of 2m : 1p. In our experiments, in several diploid maize lines, after their pollination with tetraploid pollen, the formation of large plump kernels was observed, from which diploid maternal-type plants developed, the maternal-type phenotype, as well as the hybrid endosperm phenotype, were confirmed by the expression of genetic markers. It has been suggested that the plump kernels in 2n × 4n crosses arise on the basis of unreduced embryo sacs (ESs) and pseudogamous apomixis, since the fusion of diploid sperms with diploid polar nuclei provides a 2 : 1 ratio of maternal to paternal genomes in the endosperm. In order to clarify the genetic nature of diploid plants phenotypically similar to maternal lines that developed from plump kernels in 2n × 4n crosses, we carried out their genotyping for all 10 chromosomes of the maize genome using polymorphic codominant SSR- and Indel-markers that differentiate the paternal line from maternal lines. As maternal lines, we used HPL AT, which has the ability to haploid parthenogenesis, KM, YuV-11, as well as the F2 B47/HPL AT hybrid plants; and as a paternal line – Chernaya Tetra(4n). It was found that in all the plants studied, when markers of five chromosomes (1, 2, 3, 4, and 9) were used, amplification of only maternal alleles was observed. However, in each of the studied plant, when using markers of other chromosomes, cases of amplification of alleles characteristic of the paternal line were noted. A hypothesis is put forward on the formation of diploid plants in 2n × 4n crosses in maize as a result of fertilization of the unreduced ESs and the subsequent elimination of chromosomes, predominantly of the pollen parent.

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Diploid-tetraploid crosses as the instrument for obtaining apomictic maize plants

Cited by 3 publications

References 4 publications

Pseudogamous Apomixis in Maize and Sorghum in Diploid-Tetraploid Crosses

Pseudogamous Apomixis in Maize and Sorghum in Diploid-Tetraploid Crosses

Elimination of Chromosomes as a Mechanism for the Formation of Diploid Plants in Diploid–Tetraploid Crosses in Maize (Zea mays L.)

Elimination of Chromosomes as a Mechanism for the Formation of Diploid Plants in Diploid–Tetraploid Crosses in Maize (<i>Zea mays</i> L.)

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