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1.
G3 (Bethesda) ; 13(11)2023 11 01.
Artículo en Inglés | MEDLINE | ID: mdl-37652038

RESUMEN

Goss's wilt, caused by the Gram-positive actinobacterium Clavibacter nebraskensis, is an important bacterial disease of maize. The molecular and genetic mechanisms of resistance to the bacterium, or, in general, Gram-positive bacteria causing plant diseases, remain poorly understood. Here, we examined the genetic basis of Goss's wilt through differential gene expression, standard genome-wide association mapping (GWAS), extreme phenotype (XP) GWAS using highly resistant (R) and highly susceptible (S) lines, and quantitative trait locus (QTL) mapping using 3 bi-parental populations, identifying 11 disease association loci. Three loci were validated using near-isogenic lines or recombinant inbred lines. Our analysis indicates that Goss's wilt resistance is highly complex and major resistance genes are not commonly present. RNA sequencing of samples separately pooled from R and S lines with or without bacterial inoculation was performed, enabling identification of common and differential gene responses in R and S lines. Based on expression, in both R and S lines, the photosynthesis pathway was silenced upon infection, while stress-responsive pathways and phytohormone pathways, namely, abscisic acid, auxin, ethylene, jasmonate, and gibberellin, were markedly activated. In addition, 65 genes showed differential responses (up- or down-regulated) to infection in R and S lines. Combining genetic mapping and transcriptional data, individual candidate genes conferring Goss's wilt resistance were identified. Collectively, aspects of the genetic architecture of Goss's wilt resistance were revealed, providing foundational data for mechanistic studies.


Asunto(s)
Transcriptoma , Zea mays , Zea mays/genética , Zea mays/microbiología , Estudio de Asociación del Genoma Completo , Mapeo Cromosómico , Secuencia de Bases , Enfermedades de las Plantas/genética , Enfermedades de las Plantas/microbiología , Resistencia a la Enfermedad/genética
2.
Plant Cell ; 35(8): 2736-2749, 2023 08 02.
Artículo en Inglés | MEDLINE | ID: mdl-37233025

RESUMEN

Understanding gene regulatory networks is essential to elucidate developmental processes and environmental responses. Here, we studied regulation of a maize (Zea mays) transcription factor gene using designer transcription activator-like effectors (dTALes), which are synthetic Type III TALes of the bacterial genus Xanthomonas and serve as inducers of disease susceptibility gene transcription in host cells. The maize pathogen Xanthomonas vasicola pv. vasculorum was used to introduce 2 independent dTALes into maize cells to induced expression of the gene glossy3 (gl3), which encodes a MYB transcription factor involved in biosynthesis of cuticular wax. RNA-seq analysis of leaf samples identified, in addition to gl3, 146 genes altered in expression by the 2 dTALes. Nine of the 10 genes known to be involved in cuticular wax biosynthesis were upregulated by at least 1 of the 2 dTALes. A gene previously unknown to be associated with gl3, Zm00001d017418, which encodes aldehyde dehydrogenase, was also expressed in a dTALe-dependent manner. A chemically induced mutant and a CRISPR-Cas9 mutant of Zm00001d017418 both exhibited glossy leaf phenotypes, indicating that Zm00001d017418 is involved in biosynthesis of cuticular waxes. Bacterial protein delivery of dTALes proved to be a straightforward and practical approach for the analysis and discovery of pathway-specific genes in maize.


Asunto(s)
Factores de Transcripción , Zea mays , Zea mays/genética , Zea mays/metabolismo , Factores de Transcripción/genética , Factores de Transcripción/metabolismo , Activación Transcripcional , Bacterias/metabolismo , Proteínas Bacterianas/genética , Proteínas Bacterianas/metabolismo , Regulación de la Expresión Génica de las Plantas/genética , Ceras/metabolismo
3.
Plant Cell ; 35(7): 2527-2551, 2023 06 26.
Artículo en Inglés | MEDLINE | ID: mdl-36976907

RESUMEN

Fungi and oomycetes deliver effectors into living plant cells to suppress defenses and control plant processes needed for infection. Little is known about the mechanism by which these pathogens translocate effector proteins across the plasma membrane into the plant cytoplasm. The blast fungus Magnaporthe oryzae secretes cytoplasmic effectors into a specialized biotrophic interfacial complex (BIC) before translocation. Here, we show that cytoplasmic effectors within BICs are packaged into punctate membranous effector compartments that are occasionally observed in the host cytoplasm. Live cell imaging with fluorescently labeled proteins in rice (Oryza sativa) showed that these effector puncta colocalize with the plant plasma membrane and with CLATHRIN LIGHT CHAIN 1, a component of clathrin-mediated endocytosis (CME). Inhibiting CME using virus-induced gene silencing and chemical treatments resulted in cytoplasmic effectors in swollen BICs lacking effector puncta. By contrast, fluorescent marker colocalization, gene silencing, and chemical inhibitor studies failed to support a major role for clathrin-independent endocytosis in effector translocation. Effector localization patterns indicated that cytoplasmic effector translocation occurs underneath appressoria before invasive hyphal growth. Taken together, this study provides evidence that cytoplasmic effector translocation is mediated by CME in BICs and suggests a role for M. oryzae effectors in coopting plant endocytosis.


Asunto(s)
Ascomicetos , Magnaporthe , Oryza , Oryza/genética , Proteínas Fúngicas/genética , Proteínas Fúngicas/metabolismo , Ascomicetos/metabolismo , Enfermedades de las Plantas/microbiología
4.
Plant Biotechnol J ; 20(9): 1819-1832, 2022 09.
Artículo en Inglés | MEDLINE | ID: mdl-35656643

RESUMEN

Increasing populations and temperatures are expected to escalate food demands beyond production capacities, and the development of maize lines with better performance under heat stress is desirable. Here, we report that constitutive ectopic expression of a heterologous glutaredoxin S17 from Arabidopsis thaliana (AtGRXS17) can provide thermotolerance in maize through enhanced chaperone activity and modulation of heat stress-associated gene expression. The thermotolerant maize lines had increased protection against protein damage and yielded a sixfold increase in grain production in comparison to the non-transgenic counterparts under heat stress field conditions. The maize lines also displayed thermotolerance in the reproductive stages, resulting in improved pollen germination and the higher fidelity of fertilized ovules under heat stress conditions. Our results present a robust and simple strategy for meeting rising yield demands in maize and, possibly, other crop species in a warming global environment.


Asunto(s)
Arabidopsis , Termotolerancia , Arabidopsis/genética , Grano Comestible/genética , Oxidación-Reducción , Termotolerancia/genética , Zea mays/genética
5.
Physiol Plant ; 173(3): 1263-1279, 2021 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-34392538

RESUMEN

Sessile organisms such as plants have adopted diverse reactive oxygen species (ROS) scavenging mechanisms to mitigate damage under abiotic stress conditions. Though CGFS-type glutaredoxin (GRX) genes are important regulators of ROS homeostasis, each of their functions in crop plants have not yet been well understood. We performed a targeted mutagenesis analysis of four CGFS-type GRXs (SlGRXS14, SlGRXS15, SlGRXS16, and SlGRXS17) in tomato plants (Solanum lycopersicum) using a multiplex clustered regularly interspaced short palindromic repeats (CRISPR)/Cas9 system and found that Slgrxs mutants were more sensitive to various abiotic stresses compared with the wild-type tomatoes. Slgrxs15 mutants were embryonic lethal. Single, double, and triple combinations of Slgrxs14, 16, and 17 mutants were examined under heat, chilling, drought, heavy metal toxicity, nutrient deficiency, and short photoperiod stresses. Slgrxs14 and 17 mutants showed hypersensitivity to almost all stresses while Slgrxs16 mutants were affected by chilling stress and showed milder sensitivity to other stresses. Additionally, Slgrxs14 and 17 mutants showed delayed flowering time. Our results indicate that the CGFS-type SlGRXs have specific roles against abiotic stresses, providing valuable resources to develop tomato and, possibly, other crop species that are tolerant to multiple abiotic stresses by genetic engineering.


Asunto(s)
Solanum lycopersicum , Sequías , Glutarredoxinas/genética , Solanum lycopersicum/genética , Mutación , Estrés Fisiológico/genética
6.
Int J Mol Sci ; 22(10)2021 May 19.
Artículo en Inglés | MEDLINE | ID: mdl-34069397

RESUMEN

Drought stress is a major constraint in global maize production, causing almost 30-90% of the yield loss depending upon growth stage and the degree and duration of the stress. Here, we report that ectopic expression of Arabidopsis glutaredoxin S17 (AtGRXS17) in field grown maize conferred tolerance to drought stress during the reproductive stage, which is the most drought sensitive stage for seed set and, consequently, grain yield. AtGRXS17-expressing maize lines displayed higher seed set in the field, resulting in 2-fold and 1.5-fold increase in yield in comparison to the non-transgenic plants when challenged with drought stress at the tasseling and silking/pollination stages, respectively. AtGRXS17-expressing lines showed higher relative water content, higher chlorophyll content, and less hydrogen peroxide accumulation than wild-type (WT) control plants under drought conditions. AtGRXS17-expressing lines also exhibited at least 2-fold more pollen germination than WT plants under drought stress. Compared to the transgenic maize, WT controls accumulated higher amount of proline, indicating that WT plants were more stressed over the same period. The results present a robust and simple strategy for meeting rising yield demands in maize under water limiting conditions.


Asunto(s)
Glutarredoxinas/genética , Glutarredoxinas/metabolismo , Estrés Fisiológico/genética , Arabidopsis/genética , Proteínas de Arabidopsis/genética , Sequías , Expresión Génica Ectópica/genética , Grano Comestible/metabolismo , Regulación de la Expresión Génica de las Plantas/genética , Plantas Modificadas Genéticamente/genética , Plantas Modificadas Genéticamente/metabolismo , Tolerancia a la Sal/genética , Estrés Fisiológico/fisiología , Termotolerancia/genética , Zea mays/genética
7.
Genome Biol ; 22(1): 175, 2021 06 09.
Artículo en Inglés | MEDLINE | ID: mdl-34108023

RESUMEN

BACKGROUND: The maize inbred line A188 is an attractive model for elucidation of gene function and improvement due to its high embryogenic capacity and many contrasting traits to the first maize reference genome, B73, and other elite lines. The lack of a genome assembly of A188 limits its use as a model for functional studies. RESULTS: Here, we present a chromosome-level genome assembly of A188 using long reads and optical maps. Comparison of A188 with B73 using both whole-genome alignments and read depths from sequencing reads identify approximately 1.1 Gb of syntenic sequences as well as extensive structural variation, including a 1.8-Mb duplication containing the Gametophyte factor1 locus for unilateral cross-incompatibility, and six inversions of 0.7 Mb or greater. Increased copy number of carotenoid cleavage dioxygenase 1 (ccd1) in A188 is associated with elevated expression during seed development. High ccd1 expression in seeds together with low expression of yellow endosperm 1 (y1) reduces carotenoid accumulation, accounting for the white seed phenotype of A188. Furthermore, transcriptome and epigenome analyses reveal enhanced expression of defense pathways and altered DNA methylation patterns of the embryonic callus. CONCLUSIONS: The A188 genome assembly provides a high-resolution sequence for a complex genome species and a foundational resource for analyses of genome variation and gene function in maize. The genome, in comparison to B73, contains extensive intra-species structural variations and other genetic differences. Expression and network analyses identify discrete profiles for embryonic callus and other tissues.


Asunto(s)
Regulación de la Expresión Génica de las Plantas , Genoma de Planta , Proteínas de Plantas/genética , Carácter Cuantitativo Heredable , Zea mays/genética , Secuencia de Bases , Mapeo Cromosómico , Metilación de ADN , Dioxigenasas/genética , Dioxigenasas/metabolismo , Endospermo/genética , Endospermo/metabolismo , Variación Genética , Endogamia , Proteínas de Plantas/clasificación , Proteínas de Plantas/metabolismo , Alineación de Secuencia , Zea mays/clasificación , Zea mays/metabolismo
8.
Biotechniques ; 68(4): 214-218, 2020 04.
Artículo en Inglés | MEDLINE | ID: mdl-31939314

RESUMEN

Artificial miRNA technology enables the generation of siRNAs to regulate the expression of targeted genes. However, the application of siRNAs to alter gene expression is challenging due to their instability and requires a means to efficiently deliver siRNAs into the host. Here, we report that the siRNAs targeted to animal mRNAs can be heterologously expressed and stably produced in lettuce. We have modified rice miRNA precursors to produce siRNAs in lettuce with the potential to target mRNAs of mouse complement 3 (C3) and coagulation factor 7 (CF7). Expression of primary and mature siRNAs in the transgenic lettuce lines was confirmed via Sanger sequencing. Our study demonstrates an applicable tool to alter gene expression in the targeted host and has potential utility in siRNA-based oral therapeutics.


Asunto(s)
Lactuca , MicroARNs , Plantas Modificadas Genéticamente , ARN Interferente Pequeño , Animales , Genes de Plantas/genética , Lactuca/genética , Lactuca/metabolismo , Ratones , MicroARNs/genética , MicroARNs/metabolismo , Oryza/genética , Plantas Modificadas Genéticamente/genética , Plantas Modificadas Genéticamente/metabolismo , ARN Interferente Pequeño/genética , ARN Interferente Pequeño/metabolismo
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