Grand Naine Research Articles

First Report of Fusarium Wilt of Iholena Banana (Musa spp.) Caused by Fusarium oxysporum f. sp. cubense Tropical Race 4 in China.

Fusarium wilt, caused by Fusarium oxysporum f. sp. cubense (Foc), has been considered as the most devastating disease affecting bananas (Musa spp.) worldwide. A highly virulent strain of Foc, known as tropical race 4 (TR4), has been detected in the southeast Asia in the 1990s, and has since spread to western Asia, Australia, the Middle East, southern Africa, and South America (Viljoen et al. 2020). Foc TR4 can cause severe yield losses in Cavendish (AAA), Gros Michel (AAA), Silk (AAB), Pisang Awak (ABB) and Bluggoe (ABB) bananas (Ploetz et al. 2006). However, cooking bananas such as plantain (AAB) and Matooke (AAA) bananas, appear to be resistant (Zuo et al. 2017). Iholena bananas (AAB), a subgroup of varieties related to plantains (also known as Pacific plantains), is an important staple food in the Pacific Islands where it was domesticated. It is also popular in Peru, probably due to its nutritional value (Kepler et al. 2011) and is wildly cultivated in other South American countries (Dita et al. 2013). In December 2019, typical symptoms of banana Fusarium wilt were observed on Iholena accession 'Pacific Plantain' (ITC0210) in experimental fields located in Dongguan, Guangdong Province of China. The symptoms included leaf yellowing and pseudostem splitting. The vascular tissue inside the pseudostems was dark red to brown, and the inner rhizomes yellowish-brown. Vascular tissues from three diseased plants were sampled aseptically and placed on potato dextrose agar (PDA) containing 0.05 g/liter kanamycin. Fungal colonies typical of F. oxysporum developed rapidly, with purple-tinged white aerial mycelia and an abundance of microconidia borne in false heads on short microconidia (Nelson et al. 1983). Chlamydospores were produced singly or in pairs in hyphae and macroconidia. Molecular identification was performed using Foc race 4-specific primers (Lin et al. 2009), Foc TR4-specific primers (Dita et al. 2010), Foc race 1 and Foc STR4-specific primers (Ndayihanzamaso et al. 2020). Amplicons of expected sizes were obtained for Foc TR4 and race 4, but not for Foc race 1 and STR4. Sequencing of theITS and 18S rDNA from the three Iholena isolates and BLAST result showed a 100% similarity to the Foc TR4 reference sequences in GenBank (Foc II5, PRJNA73539 and PRJNA56513) to prove that the isolates were Foc TR4. Pathogenicity of the three isolates from Iholena bananas was determined by infecting 4-month-old Cavendish cv. 'Grand Nain' bananas and three Iholena accessions, 'Pacific Plantain' 'Tigua' and 'Uzakan', under greenhouse conditions by root immersion in a Foc conidial suspension and soil drenching at 106 conidia/ml (Dita, 2010). Control plants were treated with sterile distilled water. Three replications of five plantlets were used for each accession. After 35 days, the inoculated plantlets developed typical Fusarium wilt symptoms such as yellowing of the older leaves and discoloration of the inner rhizome. The control plants did not develop symptoms. To complete Koch's postulates, the fungus was re-isolated from inoculated plants and identified as Foc TR4 by PCR (Dita et al, 2010). The susceptibility of 'Tigua' and 'Uzakan' was also confirmed in Foc TR4-infested field trials, with both accessions developing severe Fusarium wilt symptoms. The susceptibility of Iholena bananas to Foc TR4 is of significant concern to all countries where this subgroup is cultivated for major food source, including Peru and other South American countries.

MusaNAC29-like transcription factor improves stress tolerance through modulation of phytohormone content and expression of stress responsive genes

Understanding the molecular mechanisms governed by genes and cross-talks among stress signaling pathways is vital for generating a broad view on stress responses in plants. Here, we analysed the effects of MusaNAC29-like transcription factor of banana on stress responses and report the quantitative modulation of phytohormone and flavonoid content and analysed the growth parameters and yield trait in transgenic banana plants. Expression of MusaNAC29-like transcription factor was strongly altered in responses to stress conditions and application of signaling molecules. Under control conditions, PMusaNAC29-like-GUS is activated in cells bordering xylem vessel elements and is strongly triggered in other cells types after influence of salicylic acid and abscisic acid. Transgenic banana plants of cultivar Rasthali and Grand Naine overexpressing MusaNAC29-like transcription factor displayed superior tolerance towards drought and salinity stress. LC-MS analysis indicated elevated levels of jasmonic acid and salicylic acid while content of zeatin was significantly reduced in leaves of transgenic banana lines. Transgenic banana lines displayed increased levels of gallic acid, coumaric acid, naringenin, chlorogenic acid while levels of vanillic acid and piperine were significantly reduced. Expression of stress related genes coding for antioxidants, thiol peptidase proteins, cold-regulated proteins, late embryogenesis abundant proteins, ethylene-responsive transcription factors, bHLH proteins, jasmonate-zim-domain proteins and WRKY transcription factors were significantly induced in transgenic banana lines. Though MusaNAC29-like transcription factor improved stress tolerance, its overexpression resulted in retarded growth of transgenic lines resulting in reduced yield of banana fruits.

Macropropagation in Banana (Musa spp.): Varietal Response to Media and Field Performance of Plantlets Against Suckers

The experiment was conducted during December 2020 to March 2022 at Banana Research Station, Kannara, Kerala Agricultural University, Thrissur, Kerala, India to evaluate the response of different banana varieties Nendran, Kadali, Rasthali, Neypoovan, Poovan (Palayankodan) and Grand Naine to macropropagation with two different media (sawdust and cocopeat) and to assess the performance of plantlets generated against suckers. The plantain variety nendran took the shortest time for primary (20.33 days) and secondary bud regeneration (14.33 days) with sawdust as media. Total duration from planting to hardening ranged from 75.9 days in Nendran (sawdust media) to 104.3 days in Poovan (cocopeat media). Significantly shorter duration was observed with saw dust in Nendran, Kadali, Rasthali and Grand Naine compared to cocopeat. The cost of production varied with the variety which ranged from Rs. 1.7−4.0 plantlet-1 in sawdust to Rs. 3.2−6.3 plantlet-1 in cocopeat. Macropropagated plantlets recorded higher bunch weight than suckers in all varieties. There was no significant difference between the 2 with respect to growth characters like plant height, pseudostem girth, suckers plant-1, days to bunching, days to maturity and crop duration across all varieties except for Neypoovan and Poovan. Quality characters like TSS and fruit acidity did not vary between the two planting materials.

Effect of vermicompost on vegetative growth and nutrient status of acclimatized Grand Naine banana plants

Novel approach for introducing vermicompost as an acclimatization soil for banana plants was conducted. Different potting mixture of vermicompost, vermiculite, peatmoss and sand at different ratios were used to study the effect of different agricultural media on vegetative growth and leaf mineral content of banana tissue culture plantlets, after acclimatization stage. Two different trial periods were studied; 12 and 24 weeks in these agricultural media for two seasons. Results indicated that using vermicompost combined with vermiculite and sand (33.3% for each) recorded the best results for the most vegetative growth studied parameters (plant height, plants and roots length, stem diameter, leaf width and shoot and root fresh and dry weight). Moreover, vermicompost at 50% + peat moss at 50% significantly increased total chlorophyll content in banana plants. Furthermore, N, P and K plant analysis has shown that vermicompost at 75% with peat moss gave the highest mineral content values at the two periods. Addition of vermicompost to the culture media improved in vitro-produced banana plants in greenhouse.

Induced resistance to Fusarium wilt of banana caused by Tropical Race 4 in Cavendish cv Grand Naine bananas after challenging with avirulent Fusarium spp.

In the last century, Fusarium wilt of banana (FWB) destroyed the banana cultivar Gros Michel. The Cavendish cultivars saved the global banana industry, and currently they dominate global production (~50%) and the export trade (~95%). However, a new strain called Tropical Race 4 (TR4) surfaced in the late 1960’s, spread globally and greatly damages Cavendish plantations as well as manifold local varieties that are primarily grown by small holders. Presently, there is no commercially available replacement for Cavendish and hence control strategies must be developed and implemented to manage FWB. Here, we studied whether it is possible to induce resistance to TR4 by pre-inoculations with different Fusarium spp. Only pre-treatments with an avirulent Race 1 strain significantly reduced disease development of TR4 in a Cavendish genotype and this effect was stable at various nutritional and pH conditions. We then used transcriptome analysis to study the molecular basis of this response. Several genes involved in plant defence responses were up-regulated during the initial stages of individual infections with TR4 and Race 1, as well as in combined treatments. In addition, a number of genes in the ethylene and jasmonate response pathways as well as several gibberellin synthesis associated genes were induced. We observed upregulation of RGA2 like genes in all treatments. Hence, RGA2 could be a key factor involved in both R1 and TR4 resistance. The data support the hypothesis that activating resistance to Race 1 in Cavendish bananas affects TR4 development and provide a first insight of gene expression during the interaction between various Fusarium spp. and banana.

Zinc Nutrition in Banana (cv. Grand Naine) at Early Growth Stage

Aims: Banana is one of the most important and globally popular table purpose fruit. This plant requires good nutrition management with respect to macro and all micronutrients combining both the organic and inorganic sources. Out of different micronutrients, zinc plays a vital role in normal growth of banana plants starting from young stage. With the view, the present experiment was carried out to study the effect of zinc nutrition on early growth of banana plants (cv. Grand Naine).
 Study Design: The experiment was laid out in Completely Randomized Design (CRD) with seven treatments and three replications.
 Place and Duration of Study: Present study has been carried out at Horticultural Farm, Department of Horticulture and Postharvest Technology, Institute of Agricuture, Visva-Bharati, Sriniketan, West Bengal in the year 2022.
 Methodology: In the present experiment, treatments comprised of different levels of zinc nutrition using zinc sulphate ZnSO4 (@ 0.25% and 0.5%) which were applied on different days (15, 30, and 45 DAP). The experiment was laid out in Completely Randomized Design (CRD) with three replications and seven treatments (ZnSO4 @ 0.25% applied at 15 and 30 DAP, ZnSO4 @ 0.5% applied at 15 and 30 DAP, ZnSO4 @ 0.25% applied at 30 and 45 DAP, ZnSO4 @ 0.5% applied at 30 and 45 DAP, ZnSO4 @ 0.25% applied at 15 and 45 DAP, ZnSO4 @ 0.5% applied at 15 and 45 DAP and control or no zinc sulphate application). The neutralization of zinc sulphate solution was done by adding required amount of lime.
 Results: It was observed that the foliar application of zinc significantly influenced plant growth. Foliar application of ZnSO4 @ 0.25% at 15 and 45 DAP recorded maximum in plant height (54.23 cm), pseudostem girth (26.82 mm), number of leaves (9.86), leaf length (36.73 cm), lamina length (29.85 cm), petiole length (5.18 cm) and leaf breadth (15.77). On the other hand, foliar application of ZnSO4 @ 0.5% at 15 and 30 DAP increased the root length (42.33 cm), shoot fresh weight (177.64 g), shoot dry weight (56.39 g), and fresh root weight (26.15 g) and dry root weight (2.85 g). The maximum number of roots (25.46) was recorded on the foliar application of ZnSO4 @ 0.5% applied at 30 and 45 DAP.
 Conclusion: Application of zinc on banana plants shows better growth than the control and the application of ZnSO4 @ 0.5%applied at 15 and 30 DAP was observed with both moderate shoot and root growth.

Trichoderma harzianum and Trichoderma asperellum are potential biocontrol agents of Meloidogyne javanica in banana cv. Grande Naine

Biological control of plant-parasitic nematodes by Trichoderma has been widely studied, especially in annual crops such as soybean and cotton, but scarcely explored in the banana crop. Phytonematodes often attack banana plantations, and the species of Meloidogyne typically are the most frequent. Depending on the nematode population, they lead to yield losses or even plant death. Despite several Trichoderma commercial products registered in Brazil as biofungicides or bionematicides, there is a single one recommended to manage Meloidogyne incognita, with no approvals for M. javanica. The objective of this study was to evaluate two Trichoderma harzianum isolates (ALL42 and IBLF006) and the T. asperellum T00 strain as antagonists of M. javanica and as inducers of systemic resistance on bananas. Greenhouse experiments were conducted by treating seedlings of the Grande Naine susceptible cultivar with conidia suspension of the isolates. The enzymatic activity of CHId and GLUeon banana leaves was evaluated at 7, 14, and 21 days after inoculation (DAI). Plant growth and nematode population were evaluated at 60 DAI. T. harzianum ALL42 and T. harzianum IBFL006 reduced the M. javanica population on banana roots by up to 55.2 % and 67.9 %, respectively, in contrast to T. asperellum T00 that was inefficient. Enzymatic activity of CHI in plants non-inoculated with the nematode was higher at 14 DAI and decreased afterward. CHI and GLU activity were higher at 21 DAI in plants treated with isolate IBFL006 and grown in infested soil. The treatments did not promote plant growth. The effect of T. harzianum isolates was tested “in vitro” as filtrate or conidia suspension on mortality of J2 individuals. ALL42 and IFBL006 non-autoclaved filtrates promoted the highest M. javanica mortality rates of 59.6 %, and 68.8 % respectively.

Molecular, Histological and Histochemical Responses of Banana Cultivars Challenged with Fusarium oxysporum f. sp. cubense with Different Levels of Virulence.

Fusarium wilt caused by Fusarium oxysporum f. sp. cubense (Foc) is the most limiting factor in the banana agribusiness worldwide. Therefore, studies regarding pathogen attack mechanisms, and especially host defense responses, in this pathosystem are of utmost importance for genetic breeding programs in the development of Foc-resistant banana cultivars. In this study, analysis at the molecular, histological and histochemical levels of the Musa spp. x Foc interaction was performed. Three Foc isolates representative of race 1 (R1), subtropical race 4 (ST4) and isolate 229A, which is a putative ST4, were inoculated in two Prata-type cultivars (Prata-Anã and BRS Platina) and one cultivar of the Cavendish type (Grand Naine). Of seven genes related to plant–pathogen interactions, five were overexpressed in ‘BRS Platina’ 12 h after inoculation (HAI) with Foc R1 and ST4 but had reduced or negative expression after inoculation with Foc 229A, according to RT–qPCR analyses. While hyphae, mycelia and spores of the Foc 229A isolate grow towards the central cylinder of the Grand Naine and Prata-Anã cultivars, culminating in the occlusion of the xylem vessels, the BRS Platina cultivar responds with increased presence of cellulose, phenolic compounds and calcium oxalate crystals, reducing colonization within 30 days after inoculation (DAI). In general, these data indicate that the cultivar BRS Platina has potential for use in banana-breeding programs focused on resistance to Foc tropical race 4 (TR4) and in aggregating information on the virulence relationships of the Foc pathogen and the defense responses of banana plants after infection.

Effects of Banana Clones and Spacing on Growth, Yield and Fruit Quality of some Banana Cultivars

Afield experiment was carried out at the National Institute for the Promotion of Horticultural Exports (NIPHE) research farm, University of Gezira, Wad Medani, Sudan, to study the effects of banana clones and spacing on vegetative growth, crop earliness, yield and yield components, fruit green life and fruit quality of some introduced banana clones under Gezira state conditions. Treatments consisted of six new banana clones, namely, Williams hybrid clone 1 (WH1), Williams hybrid clone 2 (WH2), Grand Nain clone 1 (GN1), Grand Nain clone 2 (GN2), Zelig and Bio, which were introduced from South Africa by NIPHE. The introduced clones were compared with the local cultivar Dwarf Cavendish (DC). All clones were grown at spacings of 2x2 m and 3x3 m. These treatments were arranged in a split plot design with three replications and four plants each. Results showed that vegetative growth parameters, crop earliness, yield and yield components, fruit green life and fruit quality were significantly affected by spacing and banana clones. WH1 and Zelig obtained the best vegetative growth, whereas DC obtained the worst growth. Zelig and Bio scored the highest yield and yield components, while DC scored the lowest yield in the three ratoons. WH1 took the largest number of days from shooting to harvesting, whereas Zelig recorded the highest exportable yield in the three ratoons.

Improved abiotic stress tolerance in Arabidopsis by constitutive active form of a banana DREB2 type transcription factor, MaDREB20.CA, than its native form, MaDREB20.

Banana is grown as one of the important fruit crops in tropical and subtropical regions of the world. In this study, we report induced expression of a dehydration responsive element binding 2 (DREB2) gene (MaDREB20) under individual heat, drought, and combined drought and heat stress in root of two banana genotypes Grand Nain (GN) and Hill Banana (HB). Motif analysis of MaDREB20 protein demonstrated the presence of a negative regulatory domain (NRD) or PEST motif between 150 and 184 amino acids. Transgenic Arabidopsis overexpressing MaDREB20 gene showed more survival rate, above-ground biomass, seed yield, leaf relative water content, and proline content but less ion leakage and malonaldehyde content, revealing improved tolerance against heat and drought as well as their combination than the wild-type. Overexpression of MaDREB20.CA (constitutive active form of MaDREB20 after removal of PEST region) showed better abiotic stress tolerance in Arabidopsis than its native form (MaDREB20). Transgenic Arabidopsis overexpressing MaDREB20 and MaDREB20.CA genes appeared to be associated with reduced stomatal densities under normal condition, better regulation of stomatal aperture under drought than in wild-type plants, and differential regulation of downstream target (AtTCH4 and AtIAA1) genes under heat, drought, and combined stress. Taken together, our findings revealed important functions of MaDREB20 in abiotic stress responses in transgenic Arabidopsis and could form a basis for CRISPR/Cas9-mediated removal of its NRD to enhance stress tolerance in banana.

Physico-chemical Characteristics of Different Banana Genotypes in Nagaland

The current study aims to evaluate the physico-chemical characteristics of selected banana genotypes of Nagaland. Ten banana genotypes were collected from farmer’s field and the fruits were analyzed for TSS, acidity, total sugar, reducing sugar, TSS/Acid ratio, crude protein and total carotenoids. All the analysis was done in randomized block design with three replication. In order to obtain suitable interpretation the generated data was subjected to statistical analysis such as One-way Analysis of Variance (ANOVA) at 0.05%. The experimental result revealed wide variation in the physico-chemical attributes of the selected genotypes. The maximum total soluble solids, acidity, total sugar and reducing sugar were found in Bhootmanohar, Chinichampa, Grand Naine and Meiteihei banana respectively. Highest TSS/Acid ratio, crude protein and total carotene were obtained in Bhootmanohar, Grand Naine and Bharatmani respectively. The cluster analysis of the mean of different physico-chemical characteristics revealed two major clusters and one out group.

Qualitative Changes and Flavour Profile of Banana (Musa spp) Wine during Ageing

Background: Banana is a commercial fruit of many tropical and sub-tropical nations. India is the largest producer of banana in the world. The fruit is a valuable source of carbohydrates, phenolics compounds, minerals and dietary fibre. Due to bumper production, seasonality and market gluts, huge post-harvest losses are recurring phenomena in many banana growing states in India. Hence, the present study was undertaken to evaluate the suitability of some commercial banana cultivars in the development of wine and to evaluate the qualitative changes during ageing. Methods: Wine was prepared from banana varieties (Poovan, Grand Naine, Yangambi (KM-5), Karpooravalli and Palyankodan) in 1:1 and 1:2 dilutions of pulp and water. The TSS content of the substrate was raised to 20°Brix, followed by addition of yeast @ 1.25 g/l. The must was treated with Potassium Metabisulphite (KMS) @ 0.05 g/L to inhibit the growth of other microorganisms. Fermentation was carried out for 15 days, followed by clarification and subjected to ageing for 2 months. Result: During ageing of wine, the pH and alcohol content showed an increasing trend whereas titratable acidity, total soluble solids, ascorbic acid and phenols showed a decreasing trend. The flavour profile analysis of wine revealed that ethanol, ethyl hydrogen succinate and glycerin were the major flavour compounds in banana wine. After the completion of ageing, alcohol content of banana wine ranged from 8.40 to 9.64%, phenols were in the range of 40.50 to 56.25 mg 100 g-1 and total soluble solids varied between 3.6 and 4.5° Brix. Wine prepared from the Poovan variety had the highest overall acceptability score throughout the ageing period.

Postharvest treatments of banana (Musa acuminata cv. ‘Grand Nain’, AAA) during cold and ripening temperatures with chitosan and chitosan nanoparticles to alleviate chilling injury and maintain antioxidant activity

Postharvest treatments of banana (Musa acuminata cv. ‘Grand Nain’, AAA) during cold and ripening temperatures with chitosan and chitosan nanoparticles to alleviate chilling injury and maintain antioxidant activity

Gene Expression, Histology and Histochemistry in the Interaction between Musa sp. and Pseudocercospora fijiensis.

Bananas are the main fruits responsible for feeding more than 500 million people in tropical and subtropical countries. Black Sigatoka, caused by the fungus Pseudocercospora fijiensis, is one of the most destructive disease for the crop. This fungus is mainly controlled with the use of fungicides; however, in addition to being harmful to human health, they are associated with a high cost. The development of resistant cultivars through crosses of susceptible commercial cultivars is one of the main focuses of banana breeding programs worldwide. Thus, the objective of the present study was to investigate the interaction between Musa sp. and P. fijiensis through the relative expression of candidate genes involved in the defence response to black Sigatoka in four contrasting genotypes (resistant: Calcutta 4 and Krasan Saichon; susceptible: Grand Naine and Akondro Mainty) using quantitative real-time PCR (RT–qPCR) in addition to histological and histochemical analyses to verify the defence mechanisms activated during the interaction. Differentially expressed genes (DEGs) related to the jasmonic acid and ethylene signalling pathway, GDSL-like lipases and pathogenesis-related proteins (PR-4), were identified. The number and distance between stomata were directly related to the resistance/susceptibility of each genotype. Histochemical tests showed the production of phenolic compounds and callosis as defence mechanisms activated by the resistant genotypes during the interaction process. Scanning electron microscopy (SEM) showed pathogenic structures on the leaf surface in addition to calcium oxalate crystals. The resistant genotype Krasan Saichon stood out in the analyses and has potential for use in breeding programs for resistance to black Sigatoka in banana and plantains.

Polyvinyl alcohol based functional coating incorporated with Sonneratia ovata extract: Preparation, characterization, and banana preservation

AbstractThe present work aims to develop active and biodegradable coating from polyvinyl alcohol (PVOH), agarose, and D‐glucose combined with Sonneratia ovata leaf extract (SO) for prolonging the shelf life of Grande Naine banana. In addition, the PVOH/agarose/D‐glucose/SO coating films were prepared through solvent evaporation method before applying it to banana for the purpose of characterizing vital properties required for food packaging materials. Our findings showed that the addition of SO in the polymer blend based on PVOH/agarose/D‐glucose (PAD) imparts outstanding flexibility, UV‐barrier, antioxidant, and bactericidal properties of the resultant film. It was also found that the modified coatings with SO could prolong the shelf life of bananas up to day 6th storage at 25°C. The visual appearance, development of peel color, weight loss, total soluble sugar content, and pH of banana samples confirmed that PAD‐SO coating could prevent ripening of bananas during the storage period as compared to uncoated and PAD‐coated fruits. These results suggest that PAD‐SO active coatings are a promisingly potential material for extending the shelf life of fruits.

Less Is More? Field Evaluation of Short-Stature Banana Cultivars in a Mediterranean Environment

The shift to cultivation of banana (‘Musa (AAA) Cavendish subgroup’) in screenhouses in Israel has resulted in a significant increase in plant height and, consequently, increased maintenance costs. Here, we evaluated the genetic approach to reducing plantation height. Advanced selections of the local cultivars ‘Adi’, ‘Zelig’, and ‘Gal’, selected for reduced height, were evaluated in the field. Growth and yield parameters were recorded and compared with the industry standard cv. ‘Grand Naine’ for four crop cycles. ‘Adi’ and ‘Zelig’ were shorter than ‘Grand Naine’, by 20% and 10%, respectively, whereas ‘Gal’ lost its short stature over the years. In addition, leaf area was reduced in the low-stature cultivars. Cumulative yield of ‘Adi’ and ‘Zelig’ was higher than that of ‘Grand Naine’, by 8.8% for ‘Adi’ and 5.0% for ‘Zelig’, due to higher plant density and number of harvested bunches. This multiyear study highlights ‘Adi’ and ‘Zelig’ as short-stature, highly productive cultivars with the potential for improved water-use efficiency.

High-throughput in vitro propagation and evaluation of foliar micro-morpho-anatomical stability in Musa acuminata cv. ‘Grand Nain’ using 6-benzoyladenine (BOA) in the nutrient medium

The present study was intended to develop an effective micropropagation system of the economically important ‘Grand Nain’ variety of Musa acuminata Colla (AAA) having high structural fidelity and significant potential to multiply shoots under in vitro conditions using the non-conventional cytokinin 6-benzoyladenine (BOA, C12H9N5O). The young sword sucker explants were cultured on MS medium supplemented with 4.0 mg L − 1 of BOA and 2.0 mg L − 1 IAA resulted in the formation of 6.0 shoots (3.8 cm length) within 21 days. Cytokinins with NAA resulted in callus development and stalled the shoot development. Further subculturing of shoots on MS medium containing 6.0 mg L − 1 of BOA and 2.0 mg L − 1 IAA had a significant influence on overall shoot multiplication and elongation (36.2 shoots with 7.0 cm length after 3rd subculture), while 6.0 mg L − 1 of 6-benzylaminopurine (BAP, C12H11N5) and 2.0 mg L − 1 IAA produced only 20.0 shoots. The use of BOA increased the content of the photosynthetic pigments and shoots biomass. A comparative foliar micro-morpho-structural assessment revealed that the leaves derived from BOA and IAA combination had greater leaf blade thickness, well-differentiated mesophyll tissues, larger air cavities, and developed vascular tissues. Indole-3-butyric acid (IBA) was found to be more effective in root induction than α-naphthalene acetic acid (NAA) and the highest root induction (100% response, 11.0 roots with 5.5 cm length) per shootlet was detected on MS medium augmented with 2% sucrose, 50 mg L − 1 Activated charcoal and 2.0 mg L − 1 IBA. The primary hardening of plantlets was accomplished using cocopeat, and 96.5% of the plantlets survived after secondary hardening in garden soil and vermicompost mixture under ex vitro conditions. In conclusion, the use of BOA in the medium improved the quantitative and qualitative morphometric attributes of Musa acuminata cv. ‘Grand Nain’ increasing the survival rate of in vitro raised plantlets under field conditions.

Gene expression analysis associated with tissue-specific promoters in Musa spp.

The study of promoters has become essential to elucidate genetic regulation and allow new genetic transformation strategies through plant biotechnology. The challenge is to discover and validate promoters that can regulate gene transcription spatially and/or temporally. The goal of this work was to validate genes associated with tissue-specific promoters of bananas obtained from in silico sequences and selected from the DATAMusa databank. Gene expression was quantified using RT-qPCR from different tissues: leaves, flowers, roots, unripe pulp, ripe pulp, unripe peels, and ripe peels of two different genetic groups: Prata-Anã (PA; group AAB) and Grand Naine (GN; group AAA). After the analysis of the expression of genes associated with the promoters, normalization was performed with the most stable reference genes (TUB and L2) selected using the RefFinder tool. It was determined that five genes were specific or expressed to a greater extent in some tissues than others. The EMB-23 gene was highly expressed in ripe pulp and flowers of GN, EMB-26 in the ripe pulp of GN, EMB-27 in flowers of GN, EMB-28 in roots of PA and ripe pulp and roots of GN, and EMB-31 in roots and flowers of GN and PA, and unripe pulp of GN. The in silico analysis was efficient in the identification of spatial/time-specific genes, thereby decreasing analysis time and cost, making future genetic transformation studies focusing on the application of these tissue-specific promoters possible.

Biochemical and nutritional characteristics of some commercial banana (Musa spp.) cultivars of Kerala

Biochemical and nutritional traits of 6 banana (Musa spp.) cultivars commercially cultivated in Kerala, belonging to different genomic groups viz. Pisang Lilin (AA), Grand Naine (ABB), Nendran (AAB), Karpooravalli (ABB), Njalipoovan (AB) and Yangambi (KM-5) (AAA) were evaluated. Biochemical and nutritional characters on variables such as titratable acidity (%), total soluble solids (oBrix) (TSS), total protein (g), total carbohydrates (g), total fat (%), total ash (%), crude fibre (%), vitamin C (mg), calcium (mg), potassium (mg), total phenols (mg) and total carotenoid (µg) content were laid out in a completely randomized design and subjected to one way ANOVA to determine the significance (p=.05). The cultivar Nendran (AAB) exhibited desirable biochemical and nutritional traits, particularly for titratable acidity (0.34%), TSS (23.90oB), total carbohydrates (37.51g/100g), total ash (14.89%) and crude fibre (0.90%) content. Yangambi (KM-5) (AAA) exhibited the highest values for major minerals of banana, especially calcium (168.90 mg/100g) and potassium (406.60 mg/100g). The current study reveals biochemical and nutritional variation among banana cultivars from different genomic groups, with similarities and differences overlapping even among banana cultivars from the same genomic group.

In vitro drought stress and drought-related gene expression in banana.

Banana is largely grown in tropical and subtropical climates. It is rich in various food components and has quite a high economic value. Unavailable ecological and agricultural conditions cause quantitative and qualitative losses in banana cultivation. Along with global climate change, drought stress is becoming prominent day by day. Micropropagation and rooting performance of Azman and Grand Naine banana cultivars were investigated under in vitro drought stress conditions. The expression levels of four different genes of CDPK gene family in leaf and root tissues of the rooted plants were determined with the use of qRT-PCR. Greater expression levels of four MaCDPK genes were seen in Azman cultivar than in Grand Naine cultivar. MaCDPK9 and MaCDPK21 had greater expression levels in root tissue and MaCDPK1 and MaCDPK40 genes in leaf tissues. Response of different banana cultivars to in vitro drought stress was determined in this study. The expression levels of the genes of CDPK gene family with a significant role in drought stress had significant contributions in elucidation of banana plant response to drought stress.