Agave Wilt Susceptibility by Reduction of Free Hexoses in Root Tissue of Agave tequilana Weber var. azul Commercial Plants in the Fructan Accumulation Process.

Agave tequilana stems store fructan polymers, the main carbon source for tequila production. This crop takes six or more years for industrial maturity. In conducive conditions, agave wilt disease increases the incidence of dead plants after the fourth year. Plant susceptibility induced for limited photosynthates for defense is recognized in many crops and is known as "sink-induced loss of resistance". To establish whether A. tequilana is more prone to agave wilt as it ages, because the reduction of water-soluble carbohydrates in roots, as a consequence of greater assembly of highly polymerized fructans, were quantified roots sucrose, fructose, and glucose, as well as fructans in stems of agave plants of different ages. The damage induced by inoculation with Fusarium solani or F. oxysporum in the roots or xylem bundles, respectively, was recorded. As the agave plant accumulated fructans in the stem as the main sink, the amount of these hexoses diminished in the roots of older plants, and root rot severity increased when plants were inoculated with F. solani, as evidence of more susceptibility. This knowledge could help to structure disease management that reduces the dispersion of agave wilt, dead plants, and economic losses at the end of agave's long crop cycle.

Effect of Light Quality on the seed Germination and Development of Coffee Seedlings (Coffea arabica).

Coffee (Coffea arabica) cultivation is vital to the global economic, social and cultural life of farmers. However, senescent and disease-susceptible plantations affect coffee productivity. Therefore, it is crucial to improve biotechnological strategies such as micropropagation to increase the number of plants for replanting. In this study, the dark condition (T1) and different light qualities (T0-white light 400-700 nm; T2-red light 660 nm and T3-blue light 460 nm) were evaluated to optimize the in vitro propagation of 4 and 9 month-old coffee seeds. The results showed that red light had the highest percentage, an outstanding germination rate index, which may suggest that in the case of coffee seeds could be involved phytochromes that promote germination in a red light quality. In summary, the ideal conditions for in vitro micropropagation of coffee are under white and red light condition.

Development of a rapid, high-sensitivity, low-cost fluorescence method for protein surface hydrophobicity determination using a Nanodrop fluorospectrometer.

A microvolumetric method for surface hydrophobicity (H0) determination of proteins using a Nanodrop fluorospectrometer was developed. This method reduces the protein and fluorophore quantities that are necessary for sample preparations and readings by two and three orders of magnitude, respectively, compared to conventional methods. In addition, readings can be obtained in just 2-6 s. Bovine serum albumin (BSA) and 1-anilino 8-naphthalene sulfonic acid (ANS) were used for the first optimization of appropriate fluorophore-protein conditions for H0 determination (20 µM ANS, 0.5-4 µM BSA, pH 5). Based on validation guidelines, the novel method shows linear behavior, good intraday precision, accuracy, and sensitivity. This method was robust against several factors, as determined by a Youden-Steiner test. Additional surface hydrophobicity determinations using several proteins demonstrate suitable method applicability. The present microvolumetric method provides a reliable technique to determine the H0 of proteins for pharmaceutical, biotechnological, and food applications.

Asexually propagated Agave tequilana var. azul exhibits variation in genetic markers and defence responses to Fusarium solani.

Agave (Agave tequilana var. azul) is considered a crop with low genetic diversity because it has been propagated vegetatively for centuries for commercial purposes, and consequently, it could be equally susceptible to pests and diseases. However, the present study employs plant material derived from field-grown plants exhibiting phenotypic variability in susceptibility to agave wilt. The offshoots from rhizomes of these plants were reproduced in vitro and classified as potentially resistant or susceptible. Amplified fragment length polymorphism analysis confirmed wide genetic differences among individuals, but these differences were not correlated with the observed phenotypic variability in resistance. Propagated plantlets were inoculated with Fusarium solani in two time-lapse confrontations for 72 h and 30 days. The early biochemical response showed statistically superior levels in the accumulation of shikimic acid, phenolic compounds, and chitinase activity in potentially resistant plantlets. There was an inverse correlation of these early biochemical responses and salicylic acid and the incidence of diseased root cells in isogenic plantlets in the 30-day confrontation with F. solani, suggesting that these activities and accumulation of molecules were primordial in the defence against this pathogen.