Tropical Fruit Tree Species Research Articles

Genetic associations with resistance to Meloidogyne enterolobii in guava (Psidium sp.) using cross-genera SNPs and comparative genomics to Eucalyptus highlight evolutionary conservation across the Myrtaceae.

Tropical fruit tree species constitute a yet untapped supply of outstanding diversity of taste and nutritional value, barely developed from the genetics standpoint, with scarce or no genomic resources to tackle the challenges arising in modern breeding practice. We generated a de novo genome assembly of the Psidium guajava, the super fruit "apple of the tropics", and successfully transferred 14,268 SNP probesets from Eucalyptus to Psidium at the nucleotide level, to detect genomic loci linked to resistance to the root knot nematode (RKN) Meloidogyne enterolobii derived from the wild relative P. guineense. Significantly associated loci with resistance across alternative analytical frameworks, were detected at two SNPs on chromosome 3 in a pseudo-assembly of Psidium guajava genome built using a syntenic path approach with the Eucalyptus grandis genome to determine the order and orientation of the contigs. The P. guineense-derived resistance response to RKN and disease onset is conceivably triggered by mineral nutrients and phytohormone homeostasis or signaling with the involvement of the miRNA pathway. Hotspots of mapped resistance quantitative trait loci and functional annotation in the same genomic region of Eucalyptus provide further indirect support to our results, highlighting the evolutionary conservation of genomes across genera of Myrtaceae in the adaptation to pathogens. Marker assisted introgression of the resistance loci mapped should accelerate the development of improved guava cultivars and hybrid rootstocks.

Third-generation sequencing and metabolome analysis reveal candidate genes and metabolites with altered levels in albino jackfruit seedlings

BackgroundMost plants rely on photosynthesis; therefore, albinism in plants with leaves that are white instead of green causes slow growth, dwarfing, and even death. Although albinism has been characterized in annual model plants, little is known about albino trees. Jackfruit (Artocarpus heterophyllus) is an important tropical fruit tree species. To gain insight into the mechanisms underlying the differential growth and development between albino jackfruit mutants and green seedlings, we analyzed root, stem, and leaf tissues by combining PacBio single-molecule real-time (SMRT) sequencing, high-throughput RNA-sequencing (RNA-seq), and metabolomic analysis.ResultsWe identified 8,202 differentially expressed genes (DEGs), including 225 genes encoding transcription factors (TFs), from 82,572 full-length transcripts. We also identified 298 significantly changed metabolites (SCMs) in albino A. heterophyllus seedlings from a set of 692 metabolites in A. heterophyllus seedlings. Pathway analysis revealed that these DEGs were highly enriched in metabolic pathways such as ‘photosynthesis’, ‘carbon fixation in photosynthetic organisms’, ‘glycolysis/gluconeogenesis’, and ‘TCA cycle’. Analysis of the metabolites revealed 76 SCMs associated with metabolic pathways in the albino mutants, including L-aspartic acid, citric acid, succinic acid, and fumaric acid. We selected 225 differentially expressed TF genes, 333 differentially expressed metabolic pathway genes, and 76 SCMs to construct two correlation networks. Analysis of the TF–DEG network suggested that basic helix-loop-helix (bHLH) and MYB-related TFs regulate the expression of genes involved in carbon fixation and energy metabolism to affect light responses or photomorphogenesis and normal growth. Further analysis of the DEG–SCM correlation network and the photosynthetic carbon fixation pathway suggested that NAD-ME2 (encoding a malic enzyme) and L-aspartic acid jointly inhibit carbon fixation in the albino mutants, resulting in reduced photosynthetic efficiency and inhibited plant growth.ConclusionsOur preliminarily screening identified candidate genes and metabolites specifically affected in albino A. heterophyllus seedlings, laying the foundation for further study of the regulatory mechanism of carbon fixation during photosynthesis and energy metabolism. In addition, our findings elucidate the way genes and metabolites respond in albino trees.

Photosynthesis, growth, and survival in seedlings of four tropical fruit-tree species under intense radiation

ABSTRACT In the Amazon region, agroforestry systems (AFSs) are recommended as a sustainable production alternative for local communities. A common component in Amazonian AFSs are tropical fruit trees, which can form the canopy or grow in the understory. In this study, we evaluated the effect of high radiation on photosynthesis, growth and seedling survival of four Amazonian fruit-tree species: Theobroma cacao, Eugenia stipitata, Inga edulis and Psidium guajava. Growth, chlorophyll fluorescence, gas exchange, and leaf pigments were measured in seedlings of each species grown for 12 months inside shade houses with low (8%), medium (30%) and high relative illumination (100%). Eugenia stipitata and T. cacao had the lowest acclimation capacity to high solar radiation, followed by I. edulis. Therefore, these species must be grown under intermediate light levels in early growth stages, to protect them from direct sunlight. In contrast, P. guajava seedlings demonstrated high tolerance to elevated radiation, therefore, this species can be planted under full sunlight.

Assessment of the Morphometric Variation of Fruits and Phylogenetics of Elaeocarpus ganitrus (Woodenbegar) and Elaeocarpus serratus (Ceylon Olive)

Purpose : Elaeocarpus ganitrus and E. serratus are two significant tropical fruit tree species. E. ganitrus is also important for its endocarps that are popularly known as Rudraksha. However, these are underutilized species in Sri Lanka. Therefore, present study was conducted to assess the morphometric diversity of fruits and endocarps and the phylogenetic relationships of two species using DNA barcoding markers.Research Method : The ripe fruits were collected from a set of trees of two species in Matale and Kandy districts. The fruit and endocarp size parameters were measured in two seasons and subjected to statistical analysis. The trnH-psbA and trnL-trnF sequences were obtained from the selected trees and subjected to phylogenetic analysis.Findings : The fruit size traits were predominantly affected by the intraspecific variation than the environment. The length and diameter of the endocarps were seasonal independent and tree specific. Except colour, people preferred E. serratus fruits than E. ganitrus fruits. The markers, trnH-psbA and trnL-trnF unravelled the species delimits of E. ganitrus and E. serratus. The trnL-trnF based phylogeny positioned the trees of E. ganitrus in the respective clade. E. serratus trees were cladded with E. stipularis, E. tectorius, E. dongnaiensis and E. glaber.Research Limitations: A limited sequence pop-set for Elaeocarpus spp. is available in literature for comparison. The meta-scale attempts are needed to resolve the phylogenetic relationships of Elaeocarpus germplasm.Originality / Value : The revealed morphological and phylogenetic relationships of E. ganitrus and E. serratus lay the platform for germplasm conservation and crop improvement programs in Sri Lanka.

Characterization of branch waste of several tropical fruit tree species as considerations for bioenergy resources

The aims of this research were to analyse the bio-energy properties of tree branches and determine the appropriate conversion process for the fuel source use of each species. Bio-energy properties, such as proximate analysis, calorific value, firewood value index, and hydrolysis rate of wood, and chemical component content were evaluated for branches of 11 fruit tree species (Cacao, Durian, Java plum, Rose apple, Guava, White leadtree, Mango, Gnetum, Jackfruit, Rambutan, Strawberry tree) planted in Indonesia. Among all 11 species, Rambutan, Mango, and Java plum were the best 3 species for firewood feedstock, with the score 176.6, 169.2, and 163.8 respectively. While Mango, White leadtree, and Jackfruit were the best three species for liquid bio-fuel feedstock, with the score 91.1, 86.6, and 78.0 respectively. The branches of Durian and Gnetum can be used for purposes other than bio-energy due to their low score in both two groups.

Selected Physical Properties and Microscopic Description of Ziziphus mauritiana Lam. Wood in Sudano-Sahelian Region of Nigeria

Background and Objective: Wood is a hard, fibrous tissue found in many trees. It has been used for hundreds of thousands of years for fuel, construction and industrial raw materials.  Ziziphus mauritiana is a tropical fruit tree species, belonging to the family Rhamnaceae, the specie is abundant in Sudano-sahelion region of Nigeria and it has been reported to have several medicinal uses from the leaves, stem and roots, but technical information on the use of the wood for construction purposes is limited. Therefore, determinations of selected physical and microscopic description of the wood of Z. mauritiana as a potential wood material for timber were investigated. Materials and Methods: Three matured trees of Z. mauritiana were felled from a research plantation of the Department of Forestry and Wildlife within the University of Maiduguri, in the North-eastern part of Nigeria and cross-cut into billets at the base, middle and top of the stems with estimated age of 7, 6 and 6 years old accordingly from the three sampled trees. Discs were obtained from each billet for determination of Physical properties (Bark, Bast, Sapwood, heartwood and pith proportion, Moisture content (MC), Density and some microscopic description (fibre and parenchyma cells) were all determined. Results: The average wood density of the sampled trees stood at 0.55±0.01g/cm3 and decreased from base to top. Similarly, moisture content decreased from 75.66±3.83% at the base to 54.08±1.19% at the top of the sampling height. The volumetric shrinkage is the total shrinkage in wood volume and it amounted to 10.11±3.17%. Averagely, bast accounted for 3.56±0.70%, 6.50±0.89%, 69.38±0.50 %, 16.00±3.23% and 10.38±1.96 % for bark, sapwood, heartwood and pith proportions respectively across the stem.  Conclusion: The wood of Z. mauritiana is heavy. Within tree, wood density decreased from the base to the top. The range of values obtained in this study fall within the range of 450-750 kg/m-3 for species suitable for furniture, sheeting and lining, parquet, veneer wood for peeling and slicing with large vessel size and parenchyma cells. The range of values of volumetric shrinkage along the height and radial position shows that the wood is dimensionally stable. This was evident in the low tangential–radial shrinkage ratios recorded. Thus, indicating a low risk of deformation in wood during seasoning.Â

Transcriptional reprogramming during Garcinia-type recalcitrant seed germination of Garcinia mangostana

Mangosteen (Garcinia mangostana L.) is an apomictic tropical fruit tree species which asexually produces recalcitrant seeds that are sensitive to desiccation and not viable for long-term storage. It is important to understand seed germination to inform strategy for the propagation and conservation of important plants, especially for recalcitrant species. However, little is known about the molecular physiology of tropical seed germination. Garcinia-type seed germination is unique such that the primary root and shoot emerge from the opposite ends, which is akin to in vivo direct organogenesis. For the first time, time-course transcriptome-wide gene expression during mangosteen seed germination from day 0 to day 7 was performed through RNA-sequencing with RT-qPCR validation using independent samples in triplicates. The analyses of differentially expressed genes (DEGs) and expression profile identified D3 as a key turning point for transcriptional reprogramming with an indication of a transient shift to anaerobic respiration. Particularly, the activation of ethylene signalling through increased expression of genes involved in its biosynthesis and the upregulation of ethylene-responsive transcription factors lead to the induction of direct organogenesis concurrently with seed germination. Abscisic acid (ABA) signalling appeared to play a role in stress response while gibberellin (GA) provides growth potential during mangosteen seed germination. The antagonistic relationship between ABA and GA is conserved in mangosteen as manifested by global gene expression changes based on the Arabidopsis co-expression network analysis. The current transcriptomic study comprehensively describes various molecular aspects of Garcinia-type recalcitrant seed germination and highlights similarities to in vitro somatic embryogenesis but without a differentiated embryo. This study provides insights to improve seed germination for the mass propagation of mangosteen.

Morphological and Biochemical Studies in Garcinia gummi-gutta (L.) Roxb.

Garcinia gummi-gutta, popularly known as Malabar tamarind or kodampuli is a tropical fruit tree species of high potential. Acidic fruits are used either in raw or pickled form. Fruit is highly prized for its anti-obesity property owing to high hydroxycitric acid content in its rind. Though generally cultivated for its fruits, the plant has multifaceted uses in paint manufacturing industry, as medicine, source of edible fat etc. The present study concerned comparative morphological and physicochemical analysis of two morphotypes of Malabar tamarind, which revealed significant differences among them. Fruits and leaves of these morphotypes had distinctive morphological features. A morphotype with higher rind recovery and fruit weight was identified for further crop improvement programmes. Further, dimethylsulphoxide was identified as better solvent for extraction of photosynthetic pigments, and hence could be recommended for future physiological studies.

Antidiabetic potential of polyphenolic-rich fraction of Tamarindus indica seed coat in alloxan-induced diabetic rats.

Tamarindus is a monotypic genus and belongs to the subfamily Caesalpinioideae of the family Leguminosae (Fabaceae), Tamarindus indica L., commonly known as Tamarind tree is one of the most important multipurpose tropical fruit tree species in the India, Sudan, Nigeria, Bangladesh and entire subcontinent. Hydroethanolic seed coat extract of Tamarindus indica (HETI) was assessed for presence of phytoconstituents and selection of optimum dose through acute and sub acute toxicity study. The single and multidose (14 days) study were conducted to evaluate antidiabetic potential of HETI in alloxan induced rats via determine of blood glucose level, body weight, hematological profile, extra-pancreatic glucose utilization of isolated rat hemi-diaphragm as well as histopathology of rat pancreas. Phytochemical analysis of HETI showed the presence of polyphenol like flavonoids. Single and multidose of HETI significantly (p<0.05; p<0.001) reduced blood glucose level in normoglycaemic, glucose loaded and alloxan induced hyperglycaemic animals. HETI exerts the protective effect on pancreatic β-cells as per results obtained from histopathology of animals. Moreover, HETI increased glucose uptake in isolated rat hemi-diaphragm and prevents decrease in body weight along with recovery of altered hematological parameters. The study revealed that HETI have potent hypoglycaemic action by virtue of its phytoconstituents and it can be used as a herbal medicine for diabetes.

Genetic Diversity of Underutilized Fruits in India for Environmental Sustainability

India, the centre of origin for many tropical fruit tree species, most of which are not commercially cultivated but provides significant source of livelihood support for many rural communities. The tribal inhabitants of Western Ghats, Maharashtra and North Eastern States of India were traditionally reliant on non-timber forest products and favoured local fruit species like tamarind (Tamarindusindica),jackfruit(Artocarpusheterophyllus), Indian gooseberry (Emblica officinalis), ber (Zizyphus mauritiana), etc., instead of arable food crops apart from mango and cashew, for establishing agri-horti-forestry for their livelihoods. Innumerable wild species of Citrus, Musa, Pyrusand Maluswere also prevalent in the North Eastern regions. Conversely, most of these species are in a state of neglect, while a trivial number of them are under cultivation in their native tracts by local communities for specific household uses only. These species were rendered “Underutilized” by the fact that even though they are locally abundant, they are restricted to their geographical location with dearth of scientific knowledge about them, and their current use is linked to their economic potential. These species were immensely constructive by surviving harsh agro-climatic conditions, and can be established on degraded lands, which are presently being underutilized either due to poor soil fertility or moisture scarcity. Due to unsustainable market pressures and rapid urbanization, majority of these species have come to near extinction. A holistic approach is hence proposed which includes both in-situ and ex-situ conservation strategies, as well as re-governance of the market chain. Reinforcement of their domestication through standardization of cultivation practices, facilitation for supply of planting material and increasing the demands for the produce by exploring their uses, creation of awareness among consumers and establishing a good distribution network are also crucial for attaining sustainability.

Harnessing the diversity of wild relatives of tropical fruit tree species for sustainable livelihoods

Harnessing the diversity of wild relatives of tropical fruit tree species for sustainable livelihoods

Diversity of Tropical Fruits in the Farmlands of Central Western Ghats, India and its Contribution to the Household Income

Diversity of tropical fruit tree (TFT) species, their occurrence and relationship with cultivated species in homegardens and their use by humans has rarely been studied systematically in Central Western Ghats. Among all the nine villages sampled in three bioclimatic zones, a total of 10,202 individuals belonging to 55 species were recorded. Mangifera indica was the predominantly (n=4,496) found TFT species in the home-gardens and farmlands of Uttara Kannada district. Richness was highest in up-ghat zone (10.92) and substantial lower in coastal zone (5.95) and lowest in eastern plains (4.04). Major factors contributing to low richness is the increasing replacement with exotic commercial crops (cashew) in coastal zone and the low rainfall and varied climatic conditions in eastern zone. Villages of the up-ghat zone, on an average, showed richness index of 10.92 while its value reduced nearly by half when villages of the coastal zone were considered (5.95). The lowest average richness index was found among the villages of the eastern plains (4.04). Overall, nearly one third of all TFT species (36.36 per cent) were non-native to the Western Ghats which was similar in all three zones. However, non-native trees were dominant in coastal zone (54.96%) and less prominent in up-ghat (31.58%) and eastern zone (13.42%). Average family income derived from TFT was Rs 9.595 in coastal zone, Rs 4.207 in up-ghat zone and Rs 10,591 in eastern zone. Contribution of native and non-native TFT species to total household income is low in all three zones, highest contribution was measured in eastern zone (8.18% of the total family income) and coastal zone (7.56%) and even lower in up-ghat zone (2.27%). Correlation analysis showed a positive relationship between diversity and total household income. Regression analysis showed that total family income postivily contributes to the level of TFT diversity found on farmlands, this contribtion was most significant in coastal and up-ghat zone.

Traditional Knowledge Associated with Tropical Fruit Tree Genetic Resources: Comparison of Upper-Ghat and Coastal Situation of Central Western Ghats, India

The study was taken up in two representative villages each from upper-Ghat and coastal bioclimatic zones of Uttara Kannada district, Karnataka, India with an objective to document the total tropical fruit tree species diversity and the associated traditional knowledge. About 43 tropical fruit tree (TFT) species, were recorded. Seventy four traditional knowledge associated with TFTs were recorded from the study sites. It was noted that traditional knowledge related to culinary uses and processing of TFTs were practised even today. However, traditional knowledge related to medicinal uses showed a decreasing trend, where traditional medicines are being replaced with modern medicines. Cultural Importance (CI) value was calculated for all the 42 TFT genetic resources recorded. Mango showed highest value for CI when considered for each bioclimatic zone as well as when the data was pooled over all the village. Further, other two species that showed relatively higher values of CI were jack fruit and Garcinia indica. There was a positive association of the frequency of TFTs and their CI values. Documentation of such invaluable traditional knowledge would establish the rights of local communities over their traditional knowledge and its use. It is suggested that community biodiversity register (CBR) could be effectively adopted to empower local people.

Tamarindus indica : Extent of explored potential

Tamarindus is a monotypic genus and belongs to the subfamily Caesalpinioideae of the family Leguminosae (Fabaceae), Tamarindus indica L., commonly known as Tamarind tree is one of the most important multipurpose tropical fruit tree species in the Indian subcontinent. Tamarind fruit was at first thought to be produced by an Indian palm, as the name Tamarind comes from a Persian word “Tamar-I-hind,” meaning date of India. Its name “Amlika” in Sanskrit indicates its ancient presence in the country. T.indica is used as traditional medicine in India, Africa, Pakistan, Bangladesh, Nigeria,and most of the tropical countries. It is used traditionally in abdominal pain, diarrhea and dysentery, helminthes infections, wound healing, malaria and fever, constipation, inflammation, cell cytotoxicity, gonorrhea, and eye diseases. It has numerous chemical values and is rich in phytochemicals, and hence the plant is reported to possess antidiabetic activity, antimicrobial activity, antivenomic activity, antioxidant activity, antimalarial activity, hepatoprotective activity, antiasthmatic activity, laxative activity, and anti-hyperlipidemic activity. Every part of the plant from root to leaf tips is useful for human needs. Thus the aim of the present review is to describe its morphology, and explore the phytochemical constituents, commercial utilization of the parts of the plant, and medicinal and pharmacologic activities so that T. indica's potential as multipurpose tree species can be understood.

Susceptibility to photoinhibition in seedlings of six tropical fruit tree species native to Malaysia following transplantation to a degraded land

To investigate the adaptive capacity to a strong light environment when planted on degraded land, we examined photosynthetic properties in relation to photoinhibition for the sun-leaves of six tropical fruit tree species native to Malaysia before and after transplanting. The six species were: Bouea macrophylla (Bm), Callerya atropurpurea (Ca), Canarium pilosum (Cp), Cynometra cauliflora (Cc), Morinda citrifolia (Mc) and Syzygium sp. (Ssp), which produce edible fruit for endemic animals and birds, and are candidates for corridor plantations. Based on the measurements performed before transplanting, the degree of chronic photoinhibition indicated by the decrease in pre-dawn Fv/Fm was well associated with an accumulation of excessive excitation energy in PSII indicated by a decrease in photochemical quenching (qP). Among the species, Ca and Mc showed lower degrees of photoinhibition with higher qP. Higher electron transport rates (ETR) were observed with higher qP whereas there was no significant relationship between regulatory thermal dissipation (indicated by \(F_{\rm v} /F_{\rm m}\,-\,F^\prime_{\rm v} /F^\prime _{\rm m}\)) and qP. Energy dissipation via electron transport was suggested to be important in keeping qP high and preventing photoinhibition when compared among species. Cc and Bm showed lower ETR and higher susceptibility to photoinhibition before and after transplanting. New Cp and Mc leaves developed after transplanting showed increased area-based leaf nitrogen content (Narea) and stomatal conductance (gs) compared with those before transplanting resulting in higher light-saturated net photosynthetic rates (Amax) and ETR, and contributing to mitigate photoinhibition. In contrast to these species, Ca achieved high Amax with a water conservative manner (indicated by its relatively lower gs), where the higher carboxylation efficiency accompanied with the higher Narea allowed them to maintain relatively high Amax and ETR at lower intercellular CO2 concentration.

Photosynthesis and antioxidant enzyme activity in breadfruit, jackfruit and mangosteen in Southern Yunnan, China

SummaryThe Xishuangbanna Prefecture (21°09'-22°36' N; 99°58'-101°50' E) in southern Yunnan is one of the major growing areas for tropical crops in China. Daily temperature in Winter is about 8°C lower that in Summer.The effects of season on photosynthesis and antioxidant enzyme activities were studied in the tropical fruit tree species Artocarpus altilis (breadfruit), A. heterophyllus (jackfruit) and Garcinia mangostana (mangosteen), growing in an open site. In August 2002 and January 2003, maximum net CO2 assimilation was 17.1 ± 0.3 µmoles m–2 s–1 (mean ± SE) and 10.7 ± 0.5 in breadfruit; 11.7 ± 0.2 µmoles m–2 s–1 and 10.9 ± 0.6 in jackfruit; and 8.6 ± 0.1 µmoles m–2 s–1 and 6.3 ± 0.4 in mangosteen, respectively. Concentrations of chlorophyll were lower in mangosteen and breadfruit in January than in August, while in January, photo-inhibition was evident in mangosteen and breadfruit by changes in leaf chlorophyll fluorescence. Concentrations of malondialdehyde (a product of membrane lipid peroxidation), carotenoid to chlorophyll ratios, and the activities of the antioxidant enzymes superoxide dismutase, catalase and peroxidase were higher in January than in August, in all species, especially the antioxidant enzyme activities in jackfruit. Moreover, in both August and January, mangosteen suffered severe mid-day photo-inhibition. These results indicate that jackfruit is chilling tolerant, breadfruit is chilling sensitive, and mangosteen is chilling and high-light intensity sensitive. Breadfruit and mangosteen do not appear to be suitable crops to grow outdoors in southern Yunnan, China.

Container Volume Affects Growth and Development of Wax-apple

The wax-apple [Syzygium samarangense (Bl.) Merr. &amp; Perry] is a vigorous tropical fruit tree species that has five to six growth flushes per year. One-year-old, root-bearing wax-apple trees were grown in different-sized containers filled with potting mixture to test if container volume restricts shoot and/or root growth and thereby lends itself to forcing culture. The trunk cross-sectional area (TCSA) at 15 cm above the soil was measured to assess vegetative growth. After 6 months, the TCSA had increased quadratically with container volume. At the end of the first and second year, leaf count, leaf area, leaf dry mass, stem dry mass, shoot dry mass, and root dry mass were positively correlated with container volume. However, the shoot: root ratios remained fairly constant among treatments during the experimental period. Thus, root restriction is an effective means of reducing shoot and root growth of the wax-apple.

Effect of chlorine pollution on three fruit tree species at Ranoli near Baroda, India.

This paper describes the effect of chlorine pollution from an alkalies and chemical plant at Ranoli, near Baroda, on three tropical fruit tree species-Mangifera indica L. (mango) Manilkara hexandra Dubard. (rayan) and Syzygium cumini Skeels (Jamun). As compared to controls growing in a less polluted area, trees growing close to the plant showed reduced mean leaf area, a higher percentage of leaf area damaged, a reduction in fruit yield, chlorophyll pigments, protein and carbohydrate content, and higher accumulation of chloride in the foliar tissues. The accumulation of pollutaant, chloride, in the foliar tissues was very high in mango and jamun. Based on the degree of damage to the plants, the species studied were arranged in decreasing order of their sensitivity to chlorine pollution-mango, jamun and rayan.