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Crop pedigrees incorporate information on the kinship and genetic evolutionary history of breeding materials. Complete and accurate pedigree information is vital for effective genetic improvement of crops and maximal exploitation of heterosis in crop production. It is difficult for breeders to accurately extrapolate the selection of germplasm resources with missing genealogical information based on breeding experience. In this study, an algorithm called PidTools was developed, consisting of five sets of algorithms from three core modules, for accurate pedigree identification analysis. The algorithms and associated tools are suitable for all crops, for the reconstruction and visualization of a complete pedigree for breeding materials. The algorithm and tools were validated with the model crop maize. A genotype database was constructed using Maize6H-60K array data from 5791 maize inbred lines. The pedigree of the maize inbred line Jing72464 was identified without prior provision of any parental information. The pedigree information for Zheng58 was fully identified at the genome-wide scale. With regard to group identification, the parents of a doubled-haploid group were identified based on the genotyping data. The pedigree of 21 Dan340 derived lines were visualized using PidTools. The algorithms are incorporated into a user-friendly online analytical platform, PidTools-WS, with an associated customizable toolkit program, PidTools-CLI. These analytical tools and the present results provide useful information for future maize breeding. The PidTools online analysis platform is available at https://PidTools.plantdna.site/.
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Efficient and precise genomic deletion shows promise for investigating the function of proteins in plant research and enhancing agricultural traits. In this study, we tested the PRIME-Del (PDel) strategy using a pair of prime editing guide RNAs (pegRNAs) that targeted opposite DNA strands and achieved an average deletion efficiency of 55.8% for 60 bp fragment deletions at six endogenous targets. Moreover, as high as 84.2% precise deletion efficiency was obtained for a 2000 bp deletion at the OsGS1 site in transgenic rice plants. To add the bases that were unintentionally deleted between the two nicking sequences, we used the PDel/Syn strategy, which introduced multiple synonymous base mutations in the region that had to be patched in the RT template. The PDel/Syn strategy achieved an average of 58.1% deletion efficiency at six endogenous targets, which was higher than the PDel strategy. The strategies presented in this study contribute to achieving more accurate and flexible deletions in transgenic rice plants. Supplementary Information: The online version contains supplementary material available at 10.1007/s42994-024-00153-9.
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Genome-wide analyses of maize populations have clarified the genetic basis of crop domestication and improvement. However, limited information is available on how breeding improvement reshaped the genome in the process of the formation of heterotic groups. In this study, we identified a new heterotic group (X group) based on an examination of 512 Chinese maize inbred lines. The X group was clearly distinct from the other non-H&L groups, implying that X × HIL is a new heterotic pattern. We selected the core inbred lines for an analysis of yield-related traits. Almost all yield-related traits were better in the X lines than those in the parental lines, indicating that the primary genetic improvement in the X group during breeding was yield-related traits. We generated whole-genome sequences of these lines with an average coverage of 17.35× to explore genome changes further. We analyzed the identity-by-descent (IBD) segments transferred from the two parents to the X lines and identified 29 and 28 IBD conserved regions (ICRs) from the parents PH4CV and PH6WC, respectively, accounting for 28.8% and 12.8% of the genome. We also identified 103, 89, and 131 selective sweeps (SSWs) using methods that involved the π, Tajima's D, and CLR values, respectively. Notably, 96.13% of the ICRs co-localized with SSWs, indicating that SSW signals concentrated in ICRs. We identified 171 annotated genes associated with yield-related traits in maize both in ICRs and SSWs. To identify the genetic factors associated with yield improvement, we conducted QTL mapping for 240 lines from a DH population (PH4CV × PH6WC, which are the parents of X1132X) for ten key yield-related traits and identified a total of 55 QTLs. Furthermore, we detected three QTL clusters both in ICRs and SSWs. Based on the genetic evidence, we finally identified three key genes contributing to yield improvement in breeding the X group. These findings reveal key loci and genes targeted during pedigree breeding and provide new insights for future genomic breeding.
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Insertions-deletions (InDels) are the second most abundant molecular marker in the genome and have been widely used in molecular biology research along with simple sequence repeats (SSR) and single-nucleotide polymorphisms (SNP). However, InDel variant mining and marker development usually focuses on a single type of dimorphic InDel, which does not reflect the overall InDel diversity across the genome. Here, we developed Omni InDels for maize, soybean, and rice based on sequencing data and genome assembly that included InDel variants with base lengths from 1 bp to several Mb, and we conducted a detailed classification of Omni InDels. Moreover, we screened a set of InDels that are easily detected and typed (Perfect InDels) from the Omni InDels, verified the site authenticity using 3,587 germplasm resources from 11 groups, and analyzed the germplasm resources. Furthermore, we developed a Multi-InDel set based on the Omni InDels; each Multi-InDel contains multiple InDels, which greatly increases site polymorphism, they can be detected in multiple platforms such as fluorescent capillary electrophoresis and sequencing. Finally, we developed an online database website to make Omni InDels easy to use and share and developed a visual browsing function called "Variant viewer" for all Omni InDel sites to better display the variant distribution.
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Lactate, protein lactylation (Kla), and specifically histone lactylation have recently been shown to regulate antipathogenic immune responses in mammals. Herein, after we confirmed the presence and accumulation of lactate in maize roots under drought conditions, a lactylome profiling analysis revealed that Kla modifications were invariably present in maize roots, that there were obvious differences in the lactylomes of drought-sensitive (B73) vs. drought-tolerant (Jing2416) lines, and that growing Jing2416 under drought conditions caused significant decreases in the lactylation of multiple enzymes responsible for fatty acid degradation. Inspired by findings of histone-Kla based epigenetic regulation of immune functions in animals, we initially discovered 37 Kla sites on 16 histones in the maize genome, and again detected obvious differential histone Kla-mediated trends between two lines by ChIP-Seq. Notably, only 2.7% of genes with differential histone Kla peaks detected during drought stress were commonly present in both lines, a finding demonstrating that abiotic stress triggers distinct epigenetic activities in diverse germplasm while also strongly supporting that a histone Kla layer of regulation is associated with physiological responses to drought stress. Interestingly, exogenous application of spermidine improved the drought tolerance of B73 and substantially altered the levels of lactate, protein lactylation, and histone Kla modification. Thus, beyond extending the known domain of Kla-based biochemical and epigenetic regulation from animal immunity to plant stress physiology, our study suggests the physiological, biochemical, and genetic function of "the best-known metabolic waste", lactate.
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Histonas , Ácido Láctico , Animales , Histonas/metabolismo , Zea mays/genética , Zea mays/metabolismo , Sequías , Epigénesis Genética , Estrés Fisiológico/genética , MamíferosRESUMEN
Vegetable oil is an important part of the human diet and has multiple industrial uses. The rapid increase in vegetable oil consumption has necessitated the development of viable methods for optimizing the oil content of plants. The key genes regulating the biosynthesis of maize grain oil remain mostly uncharacterized. In this study, by analyzing oil contents and performing bulked segregant RNA sequencing and mapping analyses, we determined that su1 and sh2-R mediate the shrinkage of ultra-high-oil maize grains and contribute to the increase in the grain oil content. Functional kompetitive allele-specific PCR (KASP) markers developed for su1 and sh2-R detected su1su1Sh2Sh2, Su1Su1sh2sh2, and su1su1sh2sh2 mutants among 183 sweet maize inbred lines. An RNA sequencing (RNA-seq) analysis indicated that genes differentially expressed between two conventional sweet maize lines and two ultra-high-oil maize lines were significantly associated with linoleic acid metabolism, cyanoamino acid metabolism, glutathione metabolism, alanine, aspartate, and glutamate metabolism, and nitrogen metabolism. A bulk segregant analysis and sequencing (BSA-seq) analysis identified another 88 genomic intervals related to grain oil content, 16 of which overlapped previously reported maize grain oil-related QTLs. The combined analysis of BSA-seq and RNA-seq data enabled the identification of candidate genes. The KASP markers for GRMZM2G176998 (putative WD40-like beta propeller repeat family protein), GRMZM2G021339 (homeobox-transcription factor 115), and GRMZM2G167438 (3-ketoacyl-CoA synthase) were significantly related to maize grain oil content. Another candidate gene, GRMZM2G099802 (GDSL-like lipase/acylhydrolase), catalyzes the final step of the triacylglycerol synthesis pathway and was expressed at significantly higher levels in the two ultra-high-oil maize lines than in the two conventional sweet maize lines. These novel findings will help clarify the genetic basis of the increased oil production in ultra-high-oil maize lines with grain oil contents exceeding 20%. The KASP markers developed in this study may be useful for breeding new high-oil sweet maize varieties.
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Hybrid maize displays superior heterosis and contributes over 30% of total worldwide cereal production. However, the molecular mechanisms of heterosis remain obscure. Here we show that structural variants (SVs) between the parental lines have a predominant role underpinning maize heterosis. De novo assembly and analyses of 12 maize founder inbred lines (FILs) reveal abundant genetic variations among these FILs and, through expression quantitative trait loci and association analyses, we identify several SVs contributing to genomic and phenotypic differentiations of various heterotic groups. Using a set of 91 diallel-cross F1 hybrids, we found strong positive correlations between better-parent heterosis of the F1 hybrids and the numbers of SVs between the parental lines, providing concrete genomic support for a prevalent role of genetic complementation underlying heterosis. Further, we document evidence that SVs in both ZAR1 and ZmACO2 contribute to yield heterosis in an overdominance fashion. Our results should promote genomics-based breeding of hybrid maize.
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Vigor Híbrido , Zea mays , Grano Comestible/genética , Vigor Híbrido/genética , Hibridación Genética , Fitomejoramiento , Sitios de Carácter Cuantitativo/genética , Zea mays/genética , Genoma de PlantaRESUMEN
Moderate stimuli in mitochondria improve wide-ranging stress adaptability in animals, but whether mitochondria play similar roles in plants is largely unknown. Here, we report the enhanced stress adaptability of S-type cytoplasmic male sterility (CMS-S) maize and its association with mild expression of sterilizing gene ORF355. A CMS-S maize line exhibited superior growth potential and higher yield than those of the near-isogenic N-type line in saline fields. Moderate expression of ORF355 induced the accumulation of reactive oxygen species and activated the cellular antioxidative defense system. This adaptive response was mediated by elevation of the nicotinamide adenine dinucleotide concentration and associated metabolic homeostasis. Metabolome analysis revealed broad metabolic changes in CMS-S lines, even in the absence of salinity stress. Metabolic products associated with amino acid metabolism and galactose metabolism were substantially changed, which underpinned the alteration of the antioxidative defense system in CMS-S plants. The results reveal the ORF355-mediated superior stress adaptability in CMS-S maize and might provide an important route to developing salt-tolerant maize varieties.
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Infertilidad Vegetal , Zea mays , Zea mays/genética , Infertilidad Vegetal/genética , Mitocondrias/metabolismo , Citoplasma/metabolismo , HomeostasisRESUMEN
BACKGROUND: Anthocyanins are widely applied as a marker for haploid identification after haploid induction in maize. However, the factors affecting anthocyanin biosynthesis in immature embryos and the genes regulating this process remain unclear. RESULTS: In this study, we analyzed the influence of genetic background of the male and female parents, embryo age and light exposure on anthocyanin accumulation in embryos. The results showed that light exposure was the most crucial factor enhancing the pigmentation of immature embryos. The identification accuracy of haploid embryos reached 96.4% after light exposure, but was only 11.0% following dark treatment. The total anthocyanin content was 7-fold higher in immature embryos cultured for 24 h under light conditions compared to embryos cultured in the dark. Transcriptome analysis revealed that the differentially expressed genes between immature embryos cultured for 24 h in dark and light chambers were significantly enriched in the pathways of flavonoid, flavone, flavonol and anthocyanin biosynthesis. Among the genes involved in anthocyanin biosynthesis, five up-regulated genes were identified: F3H, DFR, ANS, F3'H and the MYB transcription factor-encoding gene C1. The expression patterns of 14 selected genes were confirmed using quantitative reverse transcription-polymerase chain reaction. CONCLUSION: Light is the most important factor facilitating anthocyanin accumulation in immature embryos. After 24 h of exposure to light, the expression levels of the structural genes F3H, DFR, ANS, F3'H and transcription factor gene C1 were significantly up-regulated. This study provides new insight into the factors and key genes regulating anthocyanin biosynthesis in immature embryos, and supports improved efficiency of immature haploid embryo selection during doubled haploid breeding of maize.
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Antocianinas , Zea mays , Antocianinas/metabolismo , Zea mays/genética , Zea mays/metabolismo , Diploidia , Fitomejoramiento , Perfilación de la Expresión Génica/métodos , Factores de Transcripción/genética , Regulación de la Expresión Génica de las Plantas , Transcriptoma , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismoRESUMEN
BACKGROUND: Cytoplasmic male sterility (CMS) is a trait of economic importance in the production of hybrid seeds. In CMS-S maize, exerted anthers appear frequently in florets of field-grown female populations where only complete male-sterile plants were expected. It has been reported that these reversions are associated with the loss of sterility-conferring regions or other rearrangements in the mitochondrial genome. However, the relationship between mitochondrial function and sterility stability is largely unknown. RESULTS: In this study, we determined the ratio of plants carrying exerted anthers in the population of two CMS-S subtypes. The subtype with a high ratio of exerted anthers was designated as CMS-Sa, and the other with low ratio was designated as CMS-Sb. Through next-generation sequencing, we assembled and compared mitochondrial genomes of two CMS-S subtypes. Phylogenetic analyses revealed strong similarities between the two mitochondrial genomes. The sterility-associated regions, S plasmids, and terminal inverted repeats (TIRs) were intact in both genomes. The two subtypes maintained high transcript levels of the sterility gene orf355 in anther tissue. Most of the functional genes/proteins were identical at the nucleotide sequence and amino acid sequence levels in the two subtypes, except for NADH dehydrogenase subunit 1 (nad1). In the mitochondrial genome of CMS-Sb, a 3.3-kilobase sequence containing nad1-exon1 was absent from the second copy of the 17-kb repeat region. Consequently, we detected two copies of nad1-exon1 in CMS-Sa, but only one copy in CMS-Sb. During pollen development, nad1 transcription and mitochondrial biogenesis were induced in anthers of CMS-Sa, but not in those of CMS-Sb. We suggest that the impaired mitochondrial function in the anthers of CMS-Sb is associated with its more stable sterility. CONCLUSIONS: Comprehensive analyses revealed diversity in terms of the copy number of the mitochondrial gene nad1-exon1 between two subtypes of CMS-S maize. This difference in copy number affected the transcript levels of nad1 and mitochondrial biogenesis in anther tissue, and affected the reversion rate of CMS-S maize. The results of this study suggest the involvement of mitochondrial robustness in modulation of sterility stability in CMS-S maize.
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Genoma Mitocondrial , Infertilidad Masculina , Genoma Mitocondrial/genética , Humanos , Infertilidad Masculina/genética , Masculino , NADH Deshidrogenasa/genética , Filogenia , Infertilidad Vegetal/genética , Zea mays/genéticaRESUMEN
Maize, a major staple cereal crop in global food supply, is a thermophilic and short-day C4 plant sensitive to low-temperature stress. A low temperature is among the most severe agro-meteorological hazards in maize-growing areas. This review covers the latest research and progress in the field of chilling tolerance in maize in the last 40 years. It mainly focuses on how low-temperature stress affects the maize membrane and antioxidant systems, photosynthetic physiology, osmoregulatory substances and hormone levels. In addition, the research progress in identifying cold-tolerance QTLs (quantitative trait loci) and genes to genetically improve maize chilling toleranceis comprehensively discussed. Based on previous research, this reviewprovides anoutlook on potential future research directions and offers a reference for researchers in the maize cold-tolerance-related field.
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Lodging is a major problem in maize production, which seriously affects yield and hinders mechanized harvesting. Improving stalk strength is an effective way to improve lodging. The maize inbred line Jing2416 (J2416) was an elite germplasm in maize breeding which had strong stalk mechanical strength. To explore the characteristics its stalk strength, we conducted physiological, metabolic and transcriptomic analyses of J2416 and its parents Jing24 (J24) and 5237. At the kernel dent stage, the stalk rind penetrometer strength of J2416 was significantly higher than those of its two parents in multiple environments. The rind thickness, sclerenchyma tissue thickness, and cellulose, hemicellulose, and lignin contents of J2416 were significantly higher than those of its parents. Based on the significant differences between J2416 and 5237, we detected metabolites and gene transcripts showing differences in abundance between these two materials. A total of 212 (68.60%) metabolites and 2287 (43.34%) genes were up-regulated in J2416 compared with 5237. The phenylpropanoid and glycan synthesis/metabolism pathways were enriched in metabolites and genes that were up-regulated in J2416. Twenty-eight of the up-regulated genes in J2416 were involved in lignin, cellulose, and hemicellulose synthesis pathways. These analyses have revealed important physiological characteristics and candidate genes that will be useful for research and breeding of inbred lines with excellent stalk strength.
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Southern corn rust (SCR) caused by Puccinia polysora Underw. poses a major threat to maize production worldwide. The utilization of host SCR-resistance genes and the cultivation of resistant cultivars are the most effective, economical strategies for controlling SCR. Here, we identified and cloned a new SCR resistance gene, RppM, from the elite maize inbred line Jing2416K. RppM was found to encode a typical CC-NBS-LRR protein localized in both the nucleus and cytoplasm. This gene was constitutively expressed at all developmental stages and in all tissues examined, with the strongest expression detected in leaves at the mature stage. A transcriptome analysis provided further evidence that multiple defense systems were initiated in Jing2416K, including pathogen-associated molecular pattern-triggered immunity and effector-triggered immunity, reinforcement of cell walls, accumulation of antimicrobial compounds, and activation of phytohormone signaling pathways. Finally, we developed functional Kompetitive allele-specific PCR markers for RppM using two conserved SNP sites and successfully applied these functional markers for the detection of RppM and the cultivation of resistant maize cultivars, demonstrating their great potential utility in maize breeding.
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Broad-spectrum resistance has great values for crop breeding. However, its mechanisms are largely unknown. Here, we report the cloning of a maize NLR gene, RppK, for resistance against southern corn rust (SCR) and its cognate Avr gene, AvrRppK, from Puccinia polysora (the causal pathogen of SCR). The AvrRppK gene has no sequence variation in all examined isolates. It has high expression level during infection and can suppress pattern-triggered immunity (PTI). Further, the introgression of RppK into maize inbred lines and hybrids enhances resistance against multiple isolates of P. polysora, thereby increasing yield in the presence of SCR. Together, we show that RppK is involved in resistance against multiple P. polysora isolates and it can recognize AvrRppK, which is broadly distributed and conserved in P. polysora isolates.
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Basidiomycota , Zea mays , Basidiomycota/genética , Mapeo Cromosómico , Clonación Molecular , Resistencia a la Enfermedad/genética , Fitomejoramiento , Enfermedades de las Plantas/genética , Puccinia , Zea mays/genéticaRESUMEN
KEY MESSAGE: The novel ZmR1CQ01 allele for maize anthocyanin synthesis was identified, and the biological function and regulatory molecular mechanisms of three ZmR1 alleles were unveiled. Anthocyanins in maize are valuable to human health. The R1 gene family is one of the important regulatory genes for the tissue-specific distribution of anthocyanins. R1 gene allelic variations are abundant and its biological function and regulatory molecular mechanisms are not fully understood. By exploiting genetic mapping and transgenic verification, we found that anthocyanin pigmentation in maize leaf midrib was controlled by ZmR1 on chromosome 10. Allelism test of maize zmr1 EMS mutants confirmed that anthocyanin pigmentation in leaf sheath was also controlled by ZmR1. ZmR1CQ01 was a novel ZmR1 allelic variation obtained from purple maize. Its overexpression caused the whole maize plant to turn purple. ZmR1B73 allele confers anthocyanin accumulation in near ground leaf sheath rather than in leaf midribs. The mRNA expression level of ZmR1B73 was low in leaf midribs, resulting in no anthocyanin accumulation. ZmR1B73 overexpression promoted anthocyanin accumulation in leaf midribs. Loss of exon 5 resulted in ZmR1ZN3 allele function destruction and no anthocyanin accumulation in leaf midrib and leaf sheath. DNA affinity purification sequencing revealed 1010 genes targeted by ZmR1CQ01, including the bz2 in anthocyanin synthesis pathway. RNA-seq analysis showed 55 genes targeted by ZmR1CQ01 changed the expression level significantly, and the expression of genes encoding key enzymes in flavonoid and phenylpropanoid biosynthesis pathways were significantly up-regulated. ZmR1 functional molecular marker was developed. These results revealed the effects of transcriptional regulation and sequence variation on ZmR1 function and identified the genes targeted by ZmR1CQ01 at the genome-wide level.
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Antocianinas , Zea mays , Alelos , ADN , Regulación de la Expresión Génica de las Plantas , Pigmentación/genética , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , ARN Mensajero , Zea mays/genética , Zea mays/metabolismoRESUMEN
Along with rapid advances in high-throughput-sequencing technology, the development and application of molecular markers has been critical for the progress that has been made in crop breeding and genetic research. Desirable molecular markers should be able to rapidly genotype tens of thousands of breeding accessions with tens to hundreds of markers. In this study, we developed a multiplex molecular marker, the haplotype-tag polymorphism (HTP), that integrates Maize6H-60K array data from 3,587 maize inbred lines with 6,375 blocks from the recombination block map. After applying strict filtering criteria, we obtained 6,163 highly polymorphic HTPs, which were evenly distributed in the genome. Furthermore, we developed a genome-wide HTP analysis toolkit, HTPtools, which we used to establish an HTP database (HTPdb) covering the whole genomes of 3,587 maize inbred lines commonly used in breeding. A total of 172,921 non-redundant HTP allelic variations were obtained. Three major HTPtools modules combine seven algorithms (e.g., chain Bayes probability and the heterotic-pattern prediction algorithm) and a new plotting engine named "BCplot" that enables rapid visualization of the background information of multiple backcross groups. HTPtools was designed for big-data analyses such as complex pedigree reconstruction and maize heterotic-pattern prediction. The HTP-based analytical strategy and the toolkit developed in this study are applicable for high-throughput genotyping and for genetic mapping, germplasm resource analyses, and genomics-informed breeding in maize.
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Polimorfismo de Nucleótido Simple , Zea mays , Teorema de Bayes , Genómica , Haplotipos , Fitomejoramiento , Zea mays/genéticaRESUMEN
Drought is a major abiotic stress that harms plant cell physiology and limits the growth and productivity of crops. Maize (Zea mays L.), one of the most drought-susceptible crops, is a major food source for humans and an important resource for industrial bioenergy production; therefore, understanding the mechanisms of the drought response is essential for maize improvement. Using isotopic tagging relative quantitation (iTRAQ)-based protein labeling technology, we detected the proteomic changes in maize leaves under drought stress. Among the 3063 proteins that were identified, the abundance of 214 and 148 proteins increased and decreased, respectively, after three days of drought treatment. These differentially abundant proteins (DAPs) were mainly involved in cell redox homeostasis, cell wall organization, photosynthesis, abscisic acid biosynthesis, and stress-response processes. Furthermore, some of the DAP abundances still differed from the control six days after the drought treatment, most of which were molecular chaperones, heat shock proteins, metabolism-related enzymes, hydrolases, and transmembrane signal receptors. The expression level of some DAPs returned to normal when the water supply was restored, but for others it did not. A significant correlation between the protein and transcript levels was observed following an RT-qPCR analysis. Finally, our research provides insights into the overall mechanism of drought-stress tolerance, and important information for breeding of drought-tolerant maize.
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Sequías , Estrés Fisiológico , Zea mays , Productos Agrícolas/fisiología , Regulación de la Expresión Génica de las Plantas , Fitomejoramiento , Hojas de la Planta/fisiología , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Proteómica , Plantones/fisiología , Zea mays/fisiologíaRESUMEN
Mitogen-activated protein kinase (MAPK or MPK) cascades consist of three protein kinase components, MAPK kinase kinases (MAPKKKs), MAPK kinases (MKKs and MPKs), which are indispensable for various plant physiological processes. The functions of MAPK families have been extensively studied in maize (Zea mays L.) and other plant species, but little is known about MAPK families in the elite Chinese maize line Huangzaosi (hzs). In this study, we observed that overall performance of Huangzaosi was substantially better than that of B73 under drought conditions at the seedling and V16 stages with a favorable root/canopy ratio. In silico analyses identified 72, 10, and 24 MAPKKKs, MKKs, and MPKs, respectively, in Huangzaosi. Examinations of phylogenetic relationships among Arabidopsis thaliana (L.) Heynh., rice (Oryza sativa L.), and maize (lines B73 and hzs), gene structures, conserved protein motifs, and chromosomal locations revealed their evolutionary relationships. The basal gene expression levels and tissue specificities of all three MAPK families in hzs reflected the diversity in the MAPK functions related to growth and development. The quantitative real-time polymerase chain reaction (qPCR) assay indicated that certain MAPK genes with high basal expression levels in the primary and crown roots responded differentially to drought between B73 and hzs, suggesting that these genes may contribute to their distinct drought tolerance at different developmental stages. The important information regarding the evolution and expression of hzs MAPK family members generated in this study provides a new avenue for the better understanding on the regulatory mechanism of MAPK cascade in the core inbred line hzs, which may be useful to guide the development of new maize cultivars with desirable traits (e.g., drought resistance).
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Oryza , Zea mays , China , Quinasas Quinasa Quinasa PAM/química , Quinasas Quinasa Quinasa PAM/genética , Quinasas Quinasa Quinasa PAM/metabolismo , Quinasas de Proteína Quinasa Activadas por Mitógenos/química , Quinasas de Proteína Quinasa Activadas por Mitógenos/genética , Quinasas de Proteína Quinasa Activadas por Mitógenos/metabolismo , Proteínas Quinasas Activadas por Mitógenos/química , Proteínas Quinasas Activadas por Mitógenos/genética , Proteínas Quinasas Activadas por Mitógenos/metabolismo , Filogenia , Zea mays/genética , Zea mays/metabolismoRESUMEN
The diversity of endophytic bacteria in the progeny is related to the parental lines. In this study, the traditional separation method was used to study the dominant endophytic bacteria of the shared paternal line and its pollen, different maternal lines and their F1 progeny. And the results showed that the dominant endophytic bacteria in maize seeds and the pollen were Bacillus and Pantoea. The Bacillus diversity of the progeny JMC121 and JN728 were the same as both the paternal line and the maternal line, including Bacillus subtilis, Bacillus velezensis, Bacillus mojavensis, and Bacillus licheniformis. The Bacillus subtilis and Bacillus velezensis in JN828 were the same as both the paternal line and the maternal line, while Bacillus licheniformis was only the same as the paternal line. Through the RAPD molecular typing, there was the same strain of Bacillus mojavensis existed in the paternal line J2416, the pollen and the progeny JN728; this meant that the paternal line passed its dominant endophytic bacteria to the progeny through pollen in vertical transmission. This study showed that the dominant endophytic bacteria in maize seeds and the pollen were Bacillus, and the diversity of F1 progeny was related to both the paternal line and the maternal line.