Losses during post-harvest management is a common problem faced in the agricultural sector. To prolong the preservation time perishable fruits, such as banana, an edible coating is one alternative method for fruit preservation method. Aims of this research are to utilise chitosan nanoparticle as a good coat and to observe its effect on Cavendish bananas (Musa acuminata AAA group) ripening process. In this study, we synthesised and characterised chitosan nanoparticle, as well as observed chitosan nanoparticle coating effect on fruit ripening process. We showed the ionic gelation method could be used to produce chitosan nanoparticles with an average diameter of 102.4 - 370 nm and the polydispersity index of 0.251 − 0.303. Fourier Transform Infrared Spectroscopy (FTIR) analysis showed a new peak which indicated an interaction of amide groups in chitosan and tripolyphosphate groups in NaTPP. A Scanning Electron Microscope (SEM) showed a smoother skin contour on coated banana compared to control (non-coated). Observations of physical characteristics of bananas ripening showed that fruits coated with chitosan nanoparticles 0.2% has a slower skin discolouration by 2-3 days compared to control treatment.

Comparative Study of Nano-chitosan and Synthetic Bactericide Application on Chili Pepper (Capsicum annuum L.) Infected by Xanthomonas campestris

Agarwood is a resinous wood of great economic value produced by trees from the Thymelaeaceae family in response to stress. The natural formation of agarwood can take decades after exposure to the stressors. Artificial agarwood induction by inoculating the stem with fungi has been successfully demonstrated, but resin accumulation occurs very slowly. Cell suspension and callus cultures may serve as an alternative solution to provide a fast-growing plant material to produce artificial agarwood in a short period. Here, we induced agarwood formation in callus cultures of Aquilaria malaccensis by application of crude mycelial extracts of Fusarium solani strains GSL1 or GSL2, or methyl jasmonate (MeJA). After 20 days of treatment with elicitors, all treated calluses had less dry weight than the control group. The gas chromatography–mass spectrometry analysis identified 33 different secondary metabolites among all samples, four of which were present in all treatments and control, i.e., 1-docosene and 1-octadecene (alkenes), 4-di-tert-buthylphenol (phenolic), and benzenepropanoic acid (fatty acid). The 6-methoxy-2-(4-methoxyphenethyl)-4H-chromene-4-one, a chromone derivative, was only detected in callus elicited with the F. solani strain GSL2 and MeJA. All treated calli produced more fatty acid derivatives than the control group. We conclude that elicitors used in this study can induce the production of agarwood-related chemicals such as chromone and fatty acid in callus culture.

The Phyllanthus genus exhibits a broad distribution spanning across the majority of tropical and subtropical regions. Due to their ability to synthesize medicinal bioactive compounds such as lignans, they have been utilized historically in traditional medicine to treat a wide range of ailments. This review discusses the current knowledge on the potency of lignans for medicinal purposes, the benefit of lignans for plants, various lignans produced by Phyllanthus, and how lignan synthesis could be increased through biotic and abiotic elicitation. Finally, we present a set of connected hypotheses to explain how signaling crosstalk between endophytic microbes and drought stress responses regulates lignan production. Although the mechanisms of lignan synthesis in Phyllanthus are not fully explored, this review strongly supports the view that endophytic fungi and drought stress can increase lignan production in plants belonging to the genus Phyllanthus. The medicinal plant–endophyte–drought stress relationship helps to improve the lignan yield of Phyllanthus, which is crucial for human health and can be optimized under in vitro and in vivo conditions.

Stevia plant contains steviol glycosides, which are estimated to be 300 times sweeter than sucrose. However, conventional (in vivo) propagation of Stevia rebaudiana in Indonesia was not effective due to poor results. Therefore, an alternative method to propagate stevia plants is needed. One of them is by using in vitro method. Multiplication with a large quantity of stevia biomass in a relatively short period can be conducted by using TIS RITA® (Recipient for Automated Temporary Immersion System). This study aimed to evaluate the effect of the immersion period of the medium on growth and the medium bioconversion into the production of shoot biomass. The bioreactors were set up with 15 min and 30 min immersions periods, scheduled every 6 h, and incubated for 21 d. The result indicated that the immersion period affected the biomass and growth rate (µ). Amount of 30 min immersion showed a greater percentage of shoot multiplication, higher biomass, percentage of leaf growth, growth rate, and productivity compared to 15 min immersion. The pattern of sucrose, mineral, and inorganic compounds consumption followed the growth of plant biomass for both systems. In conclusion, 30 min immersion gave a greater efficiency medium bioconversion to plant biomass compared with 15 min immersion.

The diverse roles of non-coding RNA and DNA in cross-species communication is yet to be revealed. Once thought to only involve intra-specifically in regulating gene expression, the evidence that these genetic materials can also modulate gene expression between species that belong to different kingdoms is accumulating. Plants send small RNAs to the pathogen or parasite when they are being attacked, targeting essential mRNAs for infection or parasitism of the hosts. However, the same survival mechanism is also deployed by the pathogen or parasite to destabilize plant immune responses. In plants, it is suggested that exposure to extracellular self-DNA impedes growth, while to extracellular non-self-DNA induces the modulation of reactive oxygen species, expression of resistance related genes, epigenetic mechanism, or suppression of disease severity. Exploring the potential of secreted RNA and extracellular DNA as a green pesticide could be a promising alternative if we are to provide food for the future global population without further damaging the environment. Hence, some studies on plant secreted RNA and responses towards extracellular DNA are discussed in this review. The precise mode of action of entry and the following cascade of signaling once the plant cell is exposed to secreted RNA or extracellular DNA could be an interesting topic for future research.