Comparison of Constitutive and Inducible Maize Kernel Proteins of Genotypes Resistant or Susceptible to Aflatoxin Production

2001 ◽  
Vol 64 (11) ◽  
pp. 1785-1792 ◽  
Author(s):  
ZHI-YUAN CHEN ◽  
ROBERT L. BROWN ◽  
THOMAS E. CLEVELAND ◽  
KENNETH E. DAMANN ◽  
JOHN S. RUSSIN
Keyword(s):  
Aflatoxin Production ◽  
Maize Kernel ◽  
Antifungal Proteins ◽  
Maize Genotypes ◽  
Resistant Genotypes

Maize genotypes resistant or susceptible to aflatoxin production or contamination were compared for differences in both constitutive and inducible proteins. Five additional constitutive proteins were found to be associated with resistance in over 8 of the 10 genotypes examined. Among these, the 58- and 46-kDa proteins were identified as globulin-1 and globulin-2, respectively. Differences in the ability to induce specific antifungal proteins, such as the higher synthesis of the 22-kDa zeamatin in resistant genotypes, were also observed between resistant and susceptible kernels incubated under germinating conditions (31°C, 100% humidity). Both constitutive and inducible proteins appear to be necessary for kernel resistance. Embryo-killed kernels (unable to synthesize new proteins) supported the highest level of aflatoxins, whereas imbibed kernels (to hasten protein induction) supported the lowest among all treatments. This suggests that the synthesis of new proteins by the embryo plays an important role in conferring resistance. However, significantly lower levels of aflatoxin production in embryo-killed resistant kernels than in susceptible ones suggest that, in reality, high levels of constitutive antifungal proteins are indispensable to kernel resistance.

scholarly journals Identification of a Maize Kernel Stress-Related Protein and Its Effect on Aflatoxin Accumulation

2004 ◽  
Vol 94 (9) ◽  
pp. 938-945 ◽  
Author(s):  
Z.-Y. Chen ◽  
R. L. Brown ◽  
K. E. Damann ◽  
T. E. Cleveland
Keyword(s):  
Regulatory Gene ◽  
Aflatoxin Production ◽  
Glyoxalase I ◽  
Constitutive Activity ◽  
Aflatoxin Biosynthesis ◽  
Maize Kernel ◽  
Kernel Infection ◽  
Maize Genotypes ◽  
Aflatoxin Accumulation ◽  
Resistant Genotypes

Aflatoxins are carcinogens produced mainly by Aspergillus flavus during infection of susceptible crops such as maize. Through proteomic comparisons of maize kernel embryo proteins of resistant and susceptible genotypes, several protein spots previously were found to be unique or upregulated in resistant embryos. In the present study, one of these protein spots was sequenced and identified as glyoxalase I (GLX-I; EC 4.4.1.5). The full-length cDNA of the glyoxalase I gene (glx-I) was cloned. GLX-I constitutive activity was found to be significantly higher in the resistant maize lines compared with susceptible ones. After kernel infection by A. flavus, GLX-I activity remained lower in susceptible genotypes than in resistant genotypes. However, fungal infection significantly increased methylglyoxal (MG) levels in two of three susceptible genotypes. Further, MG was found to induce aflatoxin production in A. flavus culture at a concentration as low as 5.0 μM. The mode of action of MG may be to stimulate the expression of aflR, an aflatoxin biosynthesis regulatory gene, which was found to be significantly upregulated in the presence of 5 to 20 μM MG. These data suggest that GLX-I may play an important role in controlling MG levels inside kernels, thereby contributing to the lower levels of aflatoxins found in resistant maize genotypes.

Wax and Cutin Layers in Maize Kernels Associated with Resistance to Aflatoxin Production by Aspergillus flavus

1995 ◽  
Vol 58 (3) ◽  
pp. 296-300 ◽  
Author(s):  
BAO Z. GUO ◽  
JOHN S. RUSSIN ◽  
THOMAS E. CLEVELAND ◽  
ROBERT L. BROWN ◽  
NEIL W. WIDSTROM
Keyword(s):  
Aspergillus Flavus ◽  
Potassium Hydroxide ◽  
Aflatoxin Production ◽  
Maize Kernel ◽  
Maize Hybrids ◽  
Maize Population ◽  
Maize Genotypes ◽  
Aflatoxin Accumulation ◽  
Maize Kernels ◽  
Susceptible Group

Thirteen maize hybrids and one maize population, MAS:gk, were screened for susceptibility to aflatoxin production by Aspergillus flavus. Marked differences in aflatoxin B1 production were detected among the maize genotypes tested. Most commercial hybrids consistently supported high levels of aflatoxin accumulation. Aflatoxin levels did not differ between intact and wounded kernels of these genotypes. However, different results were obtained from 4 of the 13 hybrids and the maize population MAS:gk. Levels of aflatoxin accumulation in intact kernels of these genotypes were lower than in the previous susceptible group of genotypes. In addition, aflatoxin levels were higher in wounded than in intact kernels. MAS:gk not only supported the lowest levels of aflatoxin production in intact kernels, but aflatoxin levels in endosperm-wounded kernels also were significantly lower in MAS:gk than in wounded kernels of all tested hybrids. Treatment with KOH to remove cutin from intact kernels prior to inoculation with A. flavus effected substantial increases in aflatoxin accumulation in MAS:gk, but only marginal increases in the susceptible hybrid Pioneer 3154. Removing wax from the surface of MAS:gk kernels greatly increased the susceptibility of this genotype to aflatoxin accumulation. When wax removal was combined with treatment with potassium hydroxide (KOH) or purified cutinase, aflatoxin levels in kernels were equal to those in wounded control kernels in both genotypes. These results indicated that wax and cutin layers of maize kernel pericarps may play a role in resistance to aflatoxin accumulation in MAS:gk and some other genotypes. However, results suggest further that resistance in MAS:gk also may be due to other preformed compounds as well.

scholarly journals Infection process in resistant and susceptible maize (Zea mays L.) genotypes to Cercospora zeae-maydis (type II)

2013 ◽  
Vol 49 (No. 1) ◽  
pp. 11-18 ◽  
Author(s):  
H.J.F. Lyimo ◽  
R.C. Pratt ◽  
R.S.O.W. Mnyuku
Keyword(s):  
Zea Mays L ◽  
Unit Area ◽  
Infection Process ◽  
Type Ii ◽  
Growth Inhibitory ◽  
Maize Genotypes ◽  
Cercospora Zeae Maydis ◽  
Maize Resistance ◽  
Moderately Resistant ◽  
Resistant Genotypes

The infection process of Cercospora zeae-maydis type II (syn. Cercospora zeina Meisel and Korsman) in resistant, moderately resistant and susceptible maize genotypes was studied in the greenhouse under artificial inoculation. The percent spore germination, germ tube growth and formation of mature appressorium on leaves at 24, 36, 48, and 72 h after inoculation did not differ between resistant, moderately resistant, and susceptible maize genotypes (P ≤ 0.05). More germlings were established after penetration on susceptible than resistant and moderately resistant maize genotypes at 72, 96, 120, and 144 h after inoculation. The hyphal wefts in cells of resistant and moderately resistant genotypes were shorter than in susceptible genotypes (P ≤ 0.05). The slow pathogen growth was associated with a reduced number of conidiophores per stroma, spores per unit area and smaller lesions. The reduced pathogen growth after penetration suggests possible involvement of pathogen growth inhibitory substances in maize resistance to C. zeae-maydis type II.

Oviposition, larval arrest and establishment of Chilo partellus (Lepidoptera: Pyralidae) on maize genotypes during anthesis

1992 ◽  
Vol 82 (3) ◽  
pp. 355-360 ◽  
Author(s):  
Harish Kumar
Keyword(s):  
Chilo Partellus ◽  
Stem Borer ◽  
The Other ◽  
Maize Breeding ◽  
Feeding Sites ◽  
Maize Genotypes ◽  
Lepidoptera Pyralidae ◽  
Neonate Larvae ◽  
Larval Establishment ◽  
Resistant Genotypes

AbstractThe oviposition, larval arrest and establishment by the stem borer Chilo partellus (Swinhoe) were measured on different maize genotypes during anthesis. The maize genotypes tested were: Inbred A (Susceptible), Mp 704, MBR-8637, MBR-8650, MBR-8668, Poza Rica 7832, ER-29 SVR, Katumani Composite B, MMV 400, Bulk CG 4141, and ICZ2-CM. The moths oviposited on the middle leaves of the plant and the neonate larvae moved to leaf sheaths and ear husks to feed (arrest). As they grew older, the larvae invaded the stem, ear shanks and tassel to complete feeding (establishment) and to pupate. The response of the stem borer differed with resistant and susceptible maize genotypes at anthesis. More eggs were laid and larval arrest was higher on the susceptible than on resistant genotypes. Genotypes also differed in the resistance of feeding sites to larval establishment; the genotype Poza Rica 7832 showed resistance to larval establishment in the stems and ears, but the shank was heavily infested. By contrast, MBR 8637 showed greater resistance to larval establishment in the shank than the other genotypes. These resistance sources could be utilized effectively in a maize breeding programme to develop varieties with moderate to high levels of resistance at all potential feeding sites.

Distribution of Antifungal Proteins in Maize Kernel Tissues Using Immunochemistry

1999 ◽  
Vol 62 (3) ◽  
pp. 295-299 ◽  
Author(s):  
B. Z. GUO ◽  
T. E. CLEVELAND ◽  
R. L. BROWN ◽  
N. W. WIDSTROM ◽  
R. E. LYNCH ◽  
...  
Keyword(s):  
Western Blot ◽  
Potential Functions ◽  
Aleurone Layer ◽  
Ribosome Inactivating Protein ◽  
Maize Kernel ◽  
Antifungal Proteins ◽  
Maize Kernels ◽  
Insight Into ◽  
Tissue Prints

This study examined the distribution of two antifungal proteins, ribosome-inactivating protein (RIP) and zeamatin, in maize kernel tissues. Proteins were extracted from endosperm (including aleurone layer) and embryo tissues of imbibed maize kernels. Western blot analyses revealed that RIP-like protein was present at higher levels in endosperm than in embryo tissues, whereas zeamatin-like protein was more concentrated in embryo tissues than in endosperm tissues. However, there were three protein bands in the endosperm and two bands in the embryo that reacted to anti-RIP antibody in Western blot analyses. Tissue prints were conducted to localize the antifungal proteins. Imbibed kernels were cut longitudinally and transversely and blotted onto nitrocellulose membranes. Using antibodies against maize RIP and zeamatin, RIP was found primarily in the aleurone layer of the endosperm and glandular layer of scutellum, whereas zeamatin was located mainly in the kernel embryo. These results provide insight into the potential functions of these antifungal proteins, especially since the presence of RIP and zeamatin within maize kernels uniquely protects kernels from pathogens.

Discovery and confirmation of genes/proteins associated with maize aflatoxin resistance

2015 ◽  
Vol 8 (2) ◽  
pp. 211-224 ◽  
Author(s):  
Z.-Y. Chen ◽  
K. Rajasekaran ◽  
R. L. Brown ◽  
R. J. Sayler ◽  
D. Bhatnagar
Keyword(s):  
Resistance Mechanism ◽  
Cost Effective ◽  
Aflatoxin Production ◽  
Aflatoxin Contamination ◽  
Antifungal Proteins ◽  
Resistant Lines ◽  
Cost Effective Alternative ◽  
Maize Plants ◽  
Maize Resistance ◽  
Lytic Peptides

Maize (Zea mays L.) is one of the major crops susceptible to Aspergillus flavus infection and subsequent aflatoxin contamination. Many earlier studies indicated the roles of kernel proteins, especially constitutively expressed proteins, in maize resistance to A. flavus infection and aflatoxin production. In this review, we examined the past and current efforts in identifying maize genes and proteins from kernel, rachis, and silk tissues that may play an important role in resistance to A. flavus infection and aflatoxin contamination, as well as the efforts in determining the importance or involvement of them in maize resistance through biochemical, molecular and genetics studies. Through these studies, we gained a better understanding of host resistance mechanism: resistant lines appear to either express some stress-related and antifungal proteins at higher levels in endosperm, embryo, rachis and silk tissues before A. flavus infection or induce the expression of these proteins much faster compared to susceptible maize lines. In addition, we summarised several recent efforts in enhancing maize resistance to aflatoxin contamination using native genes from maize or heterologous and synthetic genes from other sources as well as from A. flavus. These efforts to either suppress A. flavus growth or aflatoxin production, have all shown some promising preliminary success. For example, maize plants transformed with an ?-amylase inhibitor protein from Lablab purpurea showed reduced aflatoxin levels by 56% in kernel screening assays. The antifungal potentials of transgenic maize plants expressing synthetic lytic peptides, such as cecropin-based D4E1 or tachyplesin-based AGM peptides with demonstrated anti-flavus activity (IC50 = 2.5 to 10 ?M), are yet to be assayed. Further investigation in these areas may provide a more cost-effective alternative to biocontrol in managing aflatoxin contamination in maize and other susceptible crops.

scholarly journals Identification of a Maize Kernel Pathogenesis-Related Protein and Evidence for Its Involvement in Resistance to Aspergillus flavus Infection and Aflatoxin Production

2006 ◽  
Vol 96 (1) ◽  
pp. 87-95 ◽  
Author(s):  
Z.-Y. Chen ◽  
R. L. Brown ◽  
K. Rajasekaran ◽  
K. E. Damann ◽  
T. E. Cleveland
Keyword(s):  
Aspergillus Flavus ◽  
Fungal Growth ◽  
Aflatoxin Production ◽  
Related Protein ◽  
Susceptible Genotype ◽  
Leaf Extracts ◽  
Maize Genotypes ◽  
Resistant Lines ◽  
Pathogenesis Related Protein ◽  
Pathogenesis Related

Aflatoxins are carcinogens produced by Aspergillus flavus and A. parasiticus during infection of susceptible crops such as maize. Several aflatoxin-resistant maize genotypes have been identified and kernel proteins have been suggested to play an important role in resistance. In the present study, one protein (#717), which was expressed fivefold higher in three resistant lines compared with three susceptible ones, was identified using proteomics. This protein was sequenced and identified as a pathogenesis-related protein (PR-10) based on its sequence homology. To assess the involvement of this PR-10 protein (ZmPR-10) in host resistance of maize against fungal infection and aflatoxin production, the corresponding cDNA (pr-10) was cloned. It encodes a protein of 160 amino acids with a predicted molecular mass of 16.9 kDa and an iso-electric point of 5.38. The expression of pr-10 during kernel development increased fivefold between 7 and 22 days after pollination, and was induced upon A. flavus infection in the resistant but not in the susceptible genotype. The ZmPR-10 overexpressed in Escherichia coli exhibited a ribonucleolytic and antifungal activities. Leaf extracts of transgenic tobacco plants expressing maize pr-10 also demonstrated RNase activity and inhibited the growth of A. flavus. This evidence suggests that ZmPR-10 plays a role in kernel resistance by inhibiting fungal growth of A. flavus.

scholarly journals STARCH COMPOSITION RELATED TO PHYSICAL TRAITS IN MAIZE KERNEL

2021 ◽  
Vol 25 (2) ◽  
pp. 78-81
Author(s):  
Marija Milašinović
Keyword(s):  
Amylose Content ◽  
Hardness Test ◽  
Kernel Weight ◽  
Quality Traits ◽  
Maize Kernel ◽  
Maize Genotypes ◽  
Physical Traits ◽  
Starch Composition ◽  
Highly Correlated ◽  
The Relationship

The focus of this study is on the physical quality traits and starch composition of various maize kernel genotypes grown in Serbia. Furthermore, the aim was to determine the relationship among these quality traits. Results obtained from the Stenvert hardness test showed great variability among the maize samples. The portion of the hard endosperm fraction (HE) ranged from 53.29% to 76.28%. Test weight (TWt) and 1000-kernel weight (KWt) of 10 different ZP maize genotypes ranged from 782.69 to 907.39 kgm-3 and from 128.40 to 376.50 g, respectively. The specialty maize genotypes had the highest content of amylose (27.8% and 28.9%). Yellow dent genotype, ZP 606, had the lowest amylose content in the kernel (22.3%). The results suggested that the composition of starch granule differed depending on the hardness of the endosperm. The amylose content was highly correlated with the physical traits such as TWt, KWt, density and HE.

A Note on Use of Seed Protein Markers for Identification of Aflatoxin Resistance in Peanut1

1994 ◽  
Vol 21 (2) ◽  
pp. 159-161 ◽  
Author(s):  
C. M. Bianchi-Hall ◽  
R. D. Keys ◽  
H. T. Stalker
Keyword(s):  
Secondary Metabolites ◽  
Seed Protein ◽  
Storage Proteins ◽  
Aflatoxin Production ◽  
Protein Markers ◽  
Peanut Seed ◽  
Banding Patterns ◽  
Associate Protein ◽  
Fungal Invasion ◽  
Resistant Genotypes

Abstract Fungi in the genus Aspergillus produce aflatoxins which are a group of toxic secondary metabolites. Fungal invasion of peanut seed and subsequent aflatoxin production can occur before or during harvest as well as during storage. Because storage proteins comprise a large percentage of the peanut seed, this study attempted to associate protein markers with previously reported aflatoxin-resistant genotypes. Variation was observed among 24 genotypes for electrophoretic banding patterns, but it was not possible to correlate the presence or absence of specific bands with aflatoxin resistance.

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