Glucanases and Chitinases in Mangifera indica: Identification, Classification, Phylogeny, and Expression Analysis of Defense Genes against Colletotrichum spp.

Plant glucanases and chitinases are defense proteins that participate in pathogenesis; however, very little is known about the glucanase (GLUC) and chitinase (CHIT) gene families in mango. Some mango cultivars are of great economic importance and can be affected by anthracnose, a postharvest disease caused by fungi of the genus Colletotrichum spp. This study identified and characterized 23 putative glucanases and 16 chitinases in the mango genome cv. Tommy Atkins. We used phylogenetic analyses to classify the glucanases into three subclasses (A, B, and C) and the chitinases into four classes (I, II, IV, and V). Information on the salicylic, jasmonic acid, and ethylene pathways was obtained by analyzing the cis-elements of the GLUC and CHIT class I and IV gene promoters. The expression profile of GLUC, CHIT class I, and CHIT class IV genes in mango cv. Ataulfo inoculated with two Colletotrichum spp. revealed different profile expression related to these fungi's level of virulence. In general, this study provides the basis for the functional validation of these target genes with which the regulatory mechanisms used by glucanases and chitinases as defense proteins in mango can be elucidated.

Molecular diversity of Pakistani mango (Mangifera indica L.) varieties based on microsatellite markers.

Understanding the genetic diversity of different Pakistani mango varieties is important for germplasm management and varietal characterization. Microsatellites are efficient and highly polymorphic markers for comparative genome mapping, and were used in the present study to determine the genetic relatedness and variability among 15 indigenous mango cultivars (Mangifera indica L.). Overall, 181 bands were produced using 12 simple sequence repeat (SSR) primers. Out of the 12 primers used, 10 were polymorphic and two were monomorphic. Genetic relatedness among cultivars was assessed by constructing a dendrogram using the unweighted pair group method of arithmetic means. The accessions exhibited coefficients of similarity ranging from 75 to 100%, indicating the frequent use of only a few parent cultivars and the presence of inbreeding. The primers used in the present study were found to be valuable for identifying genetic relationships among mango cultivars.

Selection of mango rosa genotypes in a breeding population using the multivariate-biplot method / Seleção de genótipos em uma população de melhoramento de manga rosa usando o método multivariado biplot

Mango (Mangifera indica L.) trees stand out among the main fruit trees cultivated in Brazil. The mango rosa fruit is a very popular local variety (landrace), especially because of their superior technological characteristics such as high contents of Vitamin C and soluble solids (SS), as well as attractive taste and color. The objective of this study was to select a breeding population of mango rosa (polyclonal variety; 5 individuals) that can simultaneously meet the fresh and processed fruit markets, using the multivariate method of principal components and the biplot graphic. The principal components, biplot graphic, and phenotype correlations were obtained using the R (2012) software. Pulp percentage and the pulp, skin, and seed mass variables can be indirectly selected using the smallest fruit diameter, which allowed an easier measurement. The P23R AREA3, P30R AREA3, and P32R AREA3 genotypes are selection candidates due to the presence of alleles, which are important agro-technological traits for mango breeding. This study showed that the biplot analysis is a valuable tool for decision making and visualization of interrelationships between variables and genotypes, facilitating the mango selection process.(AU)

Dentre as principais fruteiras cultivadas no Brasil, destaca-se a mangueira ( Mangifera indica L.). A manga rosa é uma variedade local bastante apreciada, especialmente devido a suas características tecnológicas superiores, tais como alto teor de Vitamina C, conteúdo de sólidos solúveis totais (SS), bem como sabor e cor atraentes. O objetivo deste estudo foi selecionar uma população de melhoramento de manga rosa (variedade policlonal; 5 indivíduos) que atenda simultaneamente aos mercados de frutas frescas e processadas, empregando o método multivariado de componentes principais e o gráfico biplot. Os componentes principais, o gráfico biplot e as correlações fenotípicas foram obtidos usando o software R (2012). As variáveis porcentagem de polpa e as massas de polpa, casca e semente podem ser selecionadas indiretamente por meio do diâmetro menor do fruto, que permite uma mensuração mais fácil. Os genótipos P23R ÁREA3, P30R ÁREA3, e P32R ÁREA3 são candidatos à seleção devido à presença de alelos para caracteres agrotecnológicos, que são importantes para o melhoramento da manga. Este estudo mostrou que a análise biplot é uma ferramenta valiosa para a tomada de decisão e visualização das inter-relações entre variáveis e genótipos, facilitando o processo seletivo da manga.(AU)

Development of EST-SSR and TRAP markers from transcriptome sequencing data of the mango.

Mango is one of the most commercially important fruit crops in tropical and subtropical regions. To increase the efficiency of breeding strategies, two EST-derived marker systems were developed in the present study using information from the mango fruit transcriptome. Using simple sequence repeats, 218 of 230 primer pairs showed stable amplification for 7 mango genotypes with amplicons ranging from 84 to 160 bp; 93 of the primer pairs yielded polymorphic products. The proportion of polymorphic bands ranged from 16.67 to 100%, with a mean of 55.64%. In contrast, 86 primer pairs exhibited good amplification with clear bands for target region amplification polymorphism analysis, and a total of 66 primer combinations were polymorphic. These two novel sets of EST-derived markers will be of use in future studies of genetic diversity, genetic map construction, and marker-assisted selection in mango.

Expression and enzymatic activity of phenylalanine ammonia-lyase and p-coumarate 3-hydroxylase in mango (Mangifera indica 'Ataulfo') during ripening.

Phenylalanine ammonia lyase (PAL) and p-coumarate 3-hydroxylase (C3H) are key enzymes in the phenylpropanoid pathway. The relative expression of PAL and C3H was evaluated in mango fruit cultivar 'Ataulfo' in four ripening stages (RS1, RS2, RS3, and RS4) by quantitative polymerase chain reaction. In addition, enzyme activity of PAL and C3H was determined in mango fruits during ripening. The PAL levels were downregulated at the RS2 and RS3 stages, while C3H levels were upregulated in fruits only at RS3. The enzyme activity of PAL followed a pattern that was different from that of the PAL expression, thus suggesting regulation at several levels. For C3H, a regulation at the transcriptional level is suggested because a similar pattern was revealed by its activity and transcript level. In this study, the complexity of secondary metabolite biosynthesis regulation is emphasized because PAL and C3H enzymes are involved in the biosynthesis of several secondary metabolites that are active during all mango ripening stages.

Differentially expressed genes implicated in embryo abortion of mango identified by suppression subtractive hybridization.

Embryo abortion in mango severely damages mango production worldwide. The mechanisms by which the mango embryos abort have long been an intriguing question. We used subtractive suppression hybridization to investigate the differentially expressed genes involved in this process. We generated 2 cDNA libraries from normal seed and aborted seed embryos of mango cultivar 'Jinhuang'. One thousand five hundred and seventy-two high-quality expressed sequence tags (ESTs) were obtained, with 1092 from the normal seed tester library and 480 from the aborted seed tester library. These ESTs were assembled into 783 unigenes, including 147 contigs and 636 singletons in contigs; 297 singletons in gene ontology (GO) indicated coverage of a broad range of GO categories. Seven candidate genes from different categories were selected for semi-quantitative PCR analysis, and their possible functions in embryo abortion are discussed. These data provide new insight into the genetic regulation of embryo abortion in mango and may aid in further identification of novel genes and their functions.

Allelic database and accession divergence of a Brazilian mango collection based on microsatellite markers.

Allelic patterns and genetic distances were examined in a collection of 103 foreign and Brazilian mango (Mangifera indica) accessions in order to develop a reference database to support cultivar protection and breeding programs. An UPGMA dendrogram was generated using Jaccard's coefficients from a distance matrix based on 50 alleles of 12 microsatellite loci. The base pair number was estimated by the method of inverse mobility. The cophenetic correlation was 0.8. The accessions had a coefficient of similarity from 30 to 100%, which reflects high genetic variability. Three groups were observed in the UPGMA dendrogram; the first group was formed predominantly by foreign accessions, the second group was formed by Brazilian accessions, and the Dashehari accession was isolated from the others. The 50 microsatellite alleles did not separate all 103 accessions, indicating that there are duplicates in this mango collection. These 12 microsatellites need to be validated in order to establish a reliable set to identify mango cultivars.

Cloning and expression of ethylene receptor ERS1 at various developmental and ripening stages of mango fruit.

Ethylene induces characteristic ripening reactions in climacteric fruits through its binding to histidine-kinase (HK) receptors, activating the expression of ripening genes. Ethylene receptors have been found in Arabidopsis thaliana (Brassicaceae) and some fruits; number and expression patterns differ among species. In mango, only ethylene receptor ETR1 was known. We cloned ERS1 cDNA from mango, and evaluated the expression of Mi-ERS1 and Mi-ETR1 by qPCR in developmental and ripening stages of this fruit. The Mi-ERS1 coding sequence is 1890 bp long and encodes 629 amino acids, similar to ERS1 from other fruits. Also, the amino acid sequence of ERS1 C-terminal HK domain shows the cognate fold after molecular modeling. Mi-ERS1 expression levels increased as mangoes ripened, showing the highest levels at the climacteric stage, while Mi-ETR1 levels did not change during development and ripening. We conclude that the patterns of expression of Mi-ERS1 and Mi-ETR1 differ in mango fruit.

Comparison of efficiency of distance measurement methodologies in mango (Mangifera indica) progenies based on physicochemical descriptors.

We investigated seven distance measures in a set of observations of physicochemical variables of mango (Mangifera indica) submitted to multivariate analyses (distance, projection and grouping). To estimate the distance measurements, five mango progeny (total of 25 genotypes) were analyzed, using six fruit physicochemical descriptors (fruit weight, equatorial diameter, longitudinal diameter, total soluble solids in °Brix, total titratable acidity, and pH). The distance measurements were compared by the Spearman correlation test, projection in two-dimensional space and grouping efficiency. The Spearman correlation coefficients between the seven distance measurements were, except for the Mahalanobis' generalized distance (0.41 ≤ rs ≤ 0.63), high and significant (rs ≥ 0.91; P < 0.001). Regardless of the origin of the distance matrix, the unweighted pair group method with arithmetic mean grouping method proved to be the most adequate. The various distance measurements and grouping methods gave different values for distortion (-116.5 ≤ D ≤ 74.5), cophenetic correlation (0.26 ≤ rc ≤ 0.76) and stress (-1.9 ≤ S ≤ 58.9). Choice of distance measurement and analysis methods influence the.

Genetic diversity of 'Ubá' mango tree using ISSR markers.

In this study, the genetic diversity of 'Ubá' mango trees cultivated at the Zona da Mata of Minas Gerais State, Brazil, was assessed, to identify whether there is variability in the plants grown in the region, justifying the mass selection as a breeding method. We used 102 accessions. Leaves were collected for extraction of genomic DNA, which was amplified with nine ISSR primers. The data obtained by the analysis of electrophoretic patterns were arranged in a binary matrix, considering 0 for the absence and 1 for the presence of bands. Based on these data, we performed the analysis of genetic dissimilarity and carried out the cluster analysis by the methods of Tocher and graphical dispersion. The most similar accessions are 144 and 150, both coming from Ubá, while the most divergent ones are 29 and 97, from Visconde do Rio Branco. The grouping by the Tocher method separated the accessions into six groups, 94.1% of which were allocated in the first group and showed that there is no separation of accessions depending on the sampling sites. The 3D scatter plot reinforces this conclusion. There is genetic variability among the accessions of 'Ubá' mango tree evaluated. Therefore, it is possible to make mass selection in open-pollinated populations.

RAPD analysis of the genetic diversity of mango (Mangifera indica) germplasm in Brazil.

We evaluated genetic variability of mango (Mangifera indica) accessions maintained in the Active Germplasm Bank of Embrapa Meio-Norte in Teresina, Piauí, Brazil, using RAPDs. Among these accessions, 35 originated from plantings in Brazil, six from the USA and one from India. Genomic DNA, extracted from leaf material using a commercial purification kit, was subjected to PCR with the primers A01, A09, G03, G10, N05, and M16. Fifty-five polymorphic loci were identified, with mean of 9.16 ± 3.31 bands per primer and 100% polymorphism. Application of unweighted pair group method using arithmetic average cluster analysis demonstrated five genotypic groups among the accessions examined. The genotypes Rosa 41, Rosa 48 and Rosa 49 were highly similar (94% similarity), whereas genotypes Sensation and Rosa 18 were the most divergent (only 7% similarity). The mango accessions were found to have considerable genetic variability, demonstrating the importance of analyzing each genotype in a collection in order to efficiently maintain the germplasm collection.

Analysis of diversity among six populations of Colombian mango (Mangifera indica L. cvar. Hilacha) using RAPDs markers

Currently in Colombia, there are only records of morph-agronomic characterizations of Mangifera indica cvar. Hilacha; molecular studies on this mango variety have not been carried out. The aim of this work was to identify the genetic diversity of six populations of mango Hilacha by RAPDs markers, as a fundamental base for breeding programs, conservation and selection of promissory materials for the fruit industry at the national level. From 60 primers evaluated in the populations, five primers were selected and were launched in the six populations. Polymorphic bands of RAPDs were transformed into binary matrices, which were then processed with NTSYS-PC, POPGENE and TFPGA softwares. The overall genetic diversity, H T = 0.468 +/- 0.0016, is very similar to the average subpopulation genetic diversity, H S = 0.4431 +/- 0.0024, which revealed a small genetic differentiation among the mango Hilacha populations studied (G ST = 0.0532). This means that each population contained in average 95 percent of the total genetic diversity found in the global population analyzed. Considerable gene flow between populations (Nm = 9) was found. Finally, we recommend studying the genetic diversity of mango Hilacha populations with other molecular markers to complement the information obtained and to find similarities or differences with the results presented herein.

Antioxidant in mango (Mangifera indica L.) pulp.

This work was carried out to investigate the pulp composition of four mango cultivars (Haden, Tommy Atkins and Ubá) at the ripening stage in relation to three components with antioxidant potential (total phenolics, carotenoids and ascorbic acid). Total phenolic compound content was estimated by the Folin-Ciocalteu reagent and total carotenoid content by spectrophotometry at 450 nm. The contents of beta-carotene and total vitamin C (ascorbic acid and dehydroascorbic acid) were quantified by high performance liquid chromatography. Differences were found among the four mango cultivars in all the components analyzed. The content of phenolic compounds ranged from 48.40 (Haden) to 208.70 mg/100 g (Ubá); total carotenoid from 1.91 (Haden) to 2.63 mg/100 g (Palmer); beta-carotene from 661.27 (Palmer) to 2,220 microg/100 g (Ubá) and total ascorbic acid ranged from 9.79 (Tommy Atkins) to 77.71 mg/100 g (Ubá). These results corroborated previous information that mangoes are a good source of antioxidants in human diet.