Background: Mechanical damage to fruit during harvesting is nearly inevitable, with certain species, such as papaya, being particularly prone to spoilage. Postharvest handling can induce mechanical injuries that impair ripening and reduce shelf life, leading to significant economic losses. Although several studies have shed light on the molecular bases of mechanical damage, other aspects remain to be described (plant hormone inter-talk, physiological changes, and regulatory networks). Methods: In this study, we investigated proteomic changes in papaya fruit at two distinct ripening stages following mechanical damage. A total of 3230 proteins were identified, representing the most comprehensive proteomic analysis of papaya to date and the first assessment of proteins regulated by mechanical stress. Results: Proteins involved in ethylene biosynthesis were up-regulated on Day 2 but down-regulated on Day 12, with a similar trend observed for proteins in the abscisic acid synthesis pathway. Enzymes associated with photosynthesis, carbon fixation, primary metabolism, and carotenoid synthesis were down-regulated at both stages. In contrast, those related to plasmodesmata, calcium signaling, kinases, pathogenesis, cell wall remodeling, and proteases were up-regulated. Conclusions: These findings are thoroughly discussed, and a general model of the events triggered by mechanical impact in papaya is proposed. Our results provide a comprehensive framework for understanding papaya’s response to mechanical damage.

Background: During the last few years the home box transcription factor WUSCHEL (WUS) has been shown to cause dedifferentiation when expressed on somatic cells followed by a production of new stem cells that can lead to somatic embryogenesis or organogenesis. WUS has been shown to promote the transition from a vegetative to an embryogenic state when overexpressed. Objective/Hypothesis. The genetic in vitro transformation of meristematic tissue of Musa acuminata L. AAA, cv. “Grand Nain” was carried out using a heterologous gene WUSCHEL from Arabidopsis thaliana, via vacuum infiltration with Agrobacterium tumefaciens, to establish and ascertain if its expression modifies the progression of the explants to the embryogenesis process and or reduces the time needed for in vitro embryogenic induction phase. Methodology: Explants of proliferating shoot meristems, named “scalps”, of Musa acuminata L. AAA, cv. “Grand Nain” was transformed with WUS gene under the control of promoter GAL4, inducible by 17b-estradiol. The effect of steroid 17b-estradiol (b-Est) and homobrassinolide (HomoBra) on the in vitro somatic embryogenesis induction phase of non-transformed banana scalps was investigated. Results: The successful transformation of the explants was confirmed by PCR, for the transferred neomycin phosphotransferase II (NPTII) and the WUS gene. In addition, the expression of the red fluorescent protein (RFP) for the corresponding transferred reporter gene was verified by fluorescence microscopy in proliferated transformed tissues. Besides, the transformed tissue response to the induction of embryogenesis with either b-Est and/or HomoBra, inducers of the transgene were investigated. Implications: The improvement of the process of somatic embryogenesis in this way, generates a more effective and productive study model in a short time. Conclusions: WUS can promote the meristematic tissue-to-embryonic transition, and eventually somatic embryo formation, suggesting that the homeodomain protein can play a critical role during embryogenesis.

Los microplásticos: El enemigo silencioso de las plantas.

Protein identity and functional roles within the cell provide the landscape of proteomics and other high-throughput technologies. However, not all protein sequences are cataloged with an identity or a functional protein family. The lack of identity and functional role of a set of proteins are collectively named as the dark proteome. Key structural features are, for example, ordered sequences (with a defined structural arrangement) and disordered sequences (presenting one or more intrinsically disordered stretches). Here, we reanalyzed eight proteomic datasets and the subset of the “unknown” proteome of S. lycopersicum to describe if there is a relationship between disorder, length, and tissue-specific abundance of proteins with key structural features in the relation of ordered/disordered abundance in the protein sequences. Intriguingly, we unveil that from the S. lycopersicum proteome, the “unknown” subset represents around 10% only. We further cataloged dark proteome in terms of ordered and disordered sequences and found that proteins with disorder represent around 23% of the total “unknown” proteins. Also, we describe an amino acid composition and sequence length enrichment both, in the ordered and disordered fraction of the dark proteome. Finally, we describe that proteins within the dark proteome can be related to a specific location and abundance in an organ or tissue. An unknown protein sequence presenting a combination of specific length and degree of disorder can be explored with other biotechnological alternatives to improve responses or tolerate abiotic stress, also serving as sensors during development or ripening stages. These findings suggest an opportunity to study “protein darkness” in terms of disorder and functional associations.

Global climate change caused by natural processes results in major environmental issues that affect the world. Climate variability results in changes that cause water stress in plants. Sugarcane is a tropical grass C4, perennial and a multi-purpose industrial cash crop which serves as the main source of raw material for the production of sugar and biofuel. Farmers face the challenge to provide biotech alternatives with potential benefits and minimize potential adverse impacts on sugarcane’s production. In order to find biotechnology strategies to diminish the impact of climate change, our laboratory teamworks with micropropagation, transcriptome and genetic transformation of sugarcane using the var. MEX69290. In the transcriptome of sugarcane, a total of 536 and 750 genes were differentially regulated under normal and water stress treatment respectively, of which key genes were selected to be inserted into sugarcane for tolerance to abiotic stress. Regarding results of micropropagation, it was concluded that the continuous immersion propagation system was the best culture strategy. This may be as result of the elimination of gelling agent, which additionally helps reduce production costs.

Caña con ciencia: Mejoramiento genético de la caña en la industria azucarera