Doubled haploid (DH) technology enables the generation and evaluation of new plant genotypes in ≤ 2 years, which is in stark contrast to the 6-7 years required for conventional breeding. Recently, a few proteins including MATRILINEAL (MTL) were found to trigger haploid induction in monocot plants. However, MTL function in dicot plants remains unclear. Here, we investigate the effects of Arabidopsis PATATIN-RELATED PHOSPHOLIPASE 2A (pPLA-IIa), a maize MTL homolog, on the expression of genes that modulate pollen development and fertilization in Arabidopsis. Quantitative real-time PCR analysis showed that transcript levels of four pollen tube growth-related genes and six pollen guidance- or reception-related genes were increased in the
There is a growing preference for using doubled haploids (DHs) in maize breeding programs because they reduce the time required to generate and evaluate new lines to 2 years or less. However, there is an urgent need for efficient techniques that accurately discriminate between haploid and diploid maize kernels. Here, we investigate the effects of several hormones and chemicals on the germination of haploid and diploid maize kernels, including auxin, cytokinin, ethylene, abscisic acid (ABA) biosynthesis inhibitor (fluridone), ABA catabolism inhibitor (diniconazole), methyl jasmonate (MeJA), and NaCl. Ethylene effectively stimulated the germination of both haploid and diploid maize kernels. The ABA biosynthesis inhibitor fluridone, the ABA catabolism inhibitor diniconazole, and MeJA selectively stimulated the germination of haploid maize kernels. By contrast, gibberellin, 1-naphthaleneacetic acid (NAA), kinetin, and NaCl inhibited the germination of both haploid and diploid maize kernels. These results indicate that the germination of haploid maize kernels is selectively stimulated by fluridone and diniconazole, and suggest that ABA-mediated germination of haploid maize kernels differs from that of diploid maize kernels and other plant seeds.
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Ascorbate peroxidases (APXs) are enzymes that detoxify peroxides such as hydrogen peroxide using ascorbate. They are distributed as isoenzymes in distinct cellular compartments, such as the cytosol, mitochondria and peroxisomes, where they play essential roles in scavenging reactive oxygen species (ROS) and protecting cells against the toxic effects of these species in higher plants, algae, euglena and other organisms. APXs also respond to environmental stresses, such as salinity and drought, and rice ascorbate peroxidase 1 (OsAPx1) participates in salinity tolerance. However, it is still unclear how OsAPx1 is involved in growth and development before and after flowering. Here, we show that OsAPx1 plays an important function in seed development, including fertilization. Proteomic analysis and quantitative RT-PCR showed that protein and mRNA levels of OsAPx1 were much higher in immature seeds than in mature seeds. Plant height and grain size in an
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