Influencia de la edad en el contenido de fenoles y ligninas en Gmelina arborea (Lamiaceae) / The influence of age on the phenolic contents and lignins of Gmelina arborea (Lamiaceae)

Resumen Introducción: La melina (Gmelina arborea), es una especie de gran interés por su madera y propiedades medicinales. En Costa Rica, existen clones genéticamente superiores que se propagan sin el conocimiento de la edad ontogénica y fisiológica de los materiales. Objetivo: Evaluar la relación del contenido de fenoles y ligninas en hojas, peciolos, tallos y raíces de plantas con diferentes edades. Métodos: Los contenidos de fenoles y ligninas totales se determinaron mediante el método colorimétrico de Folin-Ciocalteu y el método de extracción alcalina, respectivamente. Para la investigación se eligieron plantas in vitro "año cero" y árboles de año y medio, cuatro, siete y 20 años. El muestreo se realizó en marzo y abril del 2021. Resultados: Se demostró que todas las partes de la planta analizadas contienen compuestos fenólicos y ligninas, independientemente de su edad. No hubo una correlación positiva entre la edad con el contenido de fenoles y ligninas para ninguna condición de desarrollo, pues los valores más altos no se obtuvieron en los árboles más longevos. Los extractos de hojas de las plantas in vitro y los árboles de siete años mostraron, respectivamente, los contenidos más altos de fenoles y ligninas para todas las condiciones (P < 0.05). Los valores promedio más bajos de compuestos fenólicos para todas las condiciones se obtuvieron en los árboles de cuatro años. Respecto a las ligninas, el contenido más bajo se presentó en las raíces más longevas, aunque la tendencia no se mantuvo para el resto de las partes de la planta. Conclusiones: La investigación muestra los primeros resultados del contenido de compuestos fenólicos y ligninas presentes en diferentes tejidos de una especie forestal de edades diferentes. Por lo tanto, son los primeros valores de referencia acerca del compromiso bioquímico para la síntesis fenólica según la edad y el estado de desarrollo específico de una planta leñosa.

Abstract Introduction: Melina (Gmelina arborea) is a tree species of great interest for its wood and medicinal properties. In Costa Rica, there are genetically superior clones that are propagated without knowledge of the ontogenic and physiological age of the materials. Objective: To evaluate how age influences the content of phenols and lignins in leaves, petioles, stems, and roots of melina plants. Methods: The total phenolic and lignins contents were determined using Folin-Ciocalteu colorimetric method and alkaline extraction method, respectively. Plants of five different ages were chosen for the investigation (in vitro plants "year 0" and trees of a year and a half, four, seven and 20 years). Sampling was done in March and April 2021. Results: All parts of the plant analyzed contain phenolic compounds and lignins, regardless of their age. There was no positive correlation between age and phenol and lignin content for any development condition, since the highest values were not obtained in the oldest trees. Leaf extracts from in vitro plants and seven-year-old trees showed, respectively, the highest phenol and lignin contents for all conditions (P < 0.05). The lowest average values of phenolic compounds for all conditions were obtained in four-year-old trees. Regarding lignins, the lowest content occurred in the oldest roots, although the trend was not maintained for the rest of the plant parts. Conclusions: This study provides the first results of the content of phenolic compounds and lignins present in different tissues of a forest species of different ages. Therefore, they are the first reference values about the biochemical commitment for phenolic synthesis according to the age and the specific developmental stage of a woody plant.

BBX transcriptional factors family in plants-a review / 生物工程学报

Transcriptional factors play important roles in plant growth, development and responses to stresses. BBX transcriptional factors are characterized with one or two B-box domains in the protein sequence. They are comprehensively involved in photomorphogenesis, flowering, shade avoidance, signal transduction of phytohormones, biotic and abiotic stress responses in plants by regulating gene transcription and interacting with other transcription factors. The classification, structure and functions of BBX of plants are reviewed in this paper.

Long non-coding RNAs: Fine-tuning the developmental responses in plants

Plant developmental biology is associated with various gene regulatory pathways involved in different phases of their lifecycle. In course of development, growth and differentiation of different organs in plants are regulated by specific sets ofgene expression. With the advances in genomic and bioinformatic techniques, particularly high-throughput sequencingtechnology, many transcriptional units with no protein-coding potential have been discovered. Previously thought to be thedark matters of genome, long non-coding RNAs (lncRNAs) are gradually gaining importance as crucial players in generegulation during different developmental phases. Some lncRNAs, showing complementarity to microRNAs (miRNAs), areused as endogenous target mimics of specific miRNA family. A number of lncRNAs can also act as natural antisensetranscripts to attenuate the expression of coding genes. Although lncRNA-mediated regulations have extensively beenstudied in animals, plant lncRNA research is still in its initial phase. The present review highlights the regulatory mechanism and different physiological aspects of lncRNAs in plant development. In plants, lncRNAs are found to be associatedwith a number of plant developmental functions such as lateral root development, vernalization, photomorphogenesis,pollen development, fiber development and nodulation. Understanding these potent roles of lncRNAs in plant developmentcan further provide novel tools for crop improvement programs in future.

Photosynthate partitioning and morphoanatomical aspects of photomorphogenic mutants of tomato / Partição de fotoassimilados e aspectos morfoanatômicos em tomateiros mutantes fotomorfogenéticos

The aim of this study was to analyze photosynthate partitioning in tomato photomorphogenic mutants at the ends of the vegetative (40 days after emergence [DAE]) and reproductive (69 DAE) stages and to determine its interaction with morphoanatomical aspects. The mutants aurea (au), phytochrome-deficient, high pigment-1 (hp1), light-exaggerated response, were studied along with the non-mutant Micro-Tom (MT) cultivar. The plants were analyzed at 40 and 68 DAE to identify photosynthate source organs and tissues as well as the target organs of remobilized photosynthate during the reproductive stage. The plants were evaluated for their internal and external morphology as well as the percentage of dry mass of their organs. Photosynthate allocation in the hp1 mutant occurred primarily in the roots and leaves, and allocation in the au mutant occurred primarily in fruits. The au mutant showed a high capacity for photosynthate remobilization to fruit during the reproductive stage, and the predominant sources of these remobilized photosynthates were the leaf spongy parenchyma, the root vascular cylinder and the marrow stem.

O objetivo deste estudo foi analisar a partição de fotoassimilados em tomateiros mutantes fotomorfogenéticos ao final da fase vegetativa, aos 40 dias após a emergência (DAE), e ao final da fase reprodutiva, aos 69 DAE, e sua interação com aspectos morfoanatômicos. Foram estudados os mutantes aurea (au), deficiente em fitocromo, e hp1, o qual expressa resposta exagerada à luz, e o tomateiro selvagem cultivar Micro-Tom (MT). As plantas foram analisadas 40 dias após a emergência (DAE) e 68 DAE, tentando identificar os órgãos e tecidos dos fotoassimilados remobilizados e seus órgãos de destino durante o estádio reprodutivo. As plantas foram avaliadas quanto à sua morfologia interna e externa e percentagem de massa seca entre os órgãos. A alocação de fotoassimilados no mutante hp1 ocorreu prioritariamente em raízes e folhas comparativamente aos demais órgãos, e no mutante au ocorreu prioritariamente em frutos comparativamente aos demais órgãos. O mutante au deteve alta capacidade de remobilização de fotoassimilados durante sua fase reprodutiva para os frutos e os fotoassimilados remobilizados tiveram origem preponderante do parênquima lacunoso foliar, do cilindro vascular radicular e da medula caulinar.

Anatomia foliar de microtomateiros fitocromo-mutantes e ultra-estrutura de cloroplastos / Leaf anatomy of micro-tomato phytochrome-mutants and chloroplast ultra-structure

Plantas fitocromo-mutantes têm sido utilizadas com o intuito de caracterizar isoladamente, dentre os demais fotorreceptores, a ação dos fitocromos sobre eventos ligados à fotomorfogênese. Raros são os estudos que relatam a ação dos fitocromos sobre aspectos estruturais, embora sejam fundamentais à compreensão do desenvolvimento das plantas. Neste trabalho, objetivou-se analisar características ultraestruturais de cloroplastos e aspectos anatômicos foliares dos microtomateiros (Solanum lycopersicum L. cv. Micro-Tom) fitocromo-mutantes aurea (subexpressa fitocromos), hp1 e atroviolacea (ambos supra-responsivos a eventos mediados por fitocromo) em plantas em estágio de floração. Observou-se que os fitocromos são responsáveis pela expressão de muitas características anatômicas da epiderme foliar, assim como do mesofilo e da ultraestrutura dos cloroplastos.

Phytochrome-mutant plants have been used for phytochrome action characterization among all photoreceptors, in events of photomorphogenesis. Studies relating the phytochrome action on structural aspects, which are fundamental to the comprehension of plant development, are rare. The objective of this work was to analyze chloroplast ultra structure and leaf anatomical characteristics of micro-tomatos (Solanum lycopersicum L. cv. Micro-Tom) phytochrome-mutants aurea (sub express phytochrome), hp1 and atroviolacea (both super express phytochrome events-mediated) in plants in the flowering stage. The results show that phytochromes are responsible for the expression of many characteristics of leaf epidermis, mesophyll and chloroplast ultra-structure.

The Progress on The Ubiquitin 26S Proteasome Pathway in Plants / 中国生物工程杂志

Selective protein degradation by the ubiquitin 26S proteasome pathway has emerged as a key regulatory mechanism in a wide variety of cellular processes.The ubiquitin/26S proteosome pathway mainly consists of ubiquitin activating enzyme(E1),ubiquitin conjugating enzyme(E2),ubiquitin protein ligase(E3),and 26S proteasome.In an ATP-dependent reaction,uibquitin(Ub) is conjugated to E1,the activated Ub is then transferred to an E2.Finally,the Ub-E2 intermediate delivers the Ub to the target protein by E3 recognition.Polyubiquinated proteins are eventually degraded by the 26S proteasome.In plants,regulated protein degradation by /26S proteasome pathway contributes significantly to development by affecting a wide range of progress,including hormone signaling,photomorphogenesis,self-incompatibility and cell cycle.The recent progress towards understanding the role of the Ub/26S proteasome pathway during plant development was reviewed.