RESUMEN
Endophytes are microbial symbionts living inside plants and have been extensively researched in recent decades for their functions associated with plant responses to environmental stress. We conducted a meta-analysis of endophyte effects on host plants' growth and fitness in response to three abiotic stress factors: drought, nitrogen deficiency, and excessive salinity. Ninety-four endophyte strains and 42 host plant species from the literature were evaluated in the analysis. Endophytes increased biomass accumulation of host plants under all three stress conditions. The stress mitigation effects by endophytes were similar among different plant taxa or functional groups with few exceptions; eudicots and C4 species gained more biomass than monocots and C3 species with endophytes, respectively, under drought conditions. Our analysis supports the effectiveness of endophytes in mitigating drought, nitrogen deficiency, and salinity stress in a wide range of host species with little evidence of plant-endophyte specificity.
Asunto(s)
Fenómenos Fisiológicos Bacterianos , Endófitos/fisiología , Hongos/fisiología , Desarrollo de la Planta , Fenómenos Fisiológicos de las Plantas , Plantas/microbiología , Bacterias/genética , Bacterias/aislamiento & purificación , Biomasa , Endófitos/genética , Endófitos/aislamiento & purificación , Hongos/genética , Hongos/aislamiento & purificación , Estrés FisiológicoRESUMEN
La formación de los compuestos volátiles durante la maduración de la guayaba (Psidium guajava L.) ha sido un aspecto ampliamente estudiado; sin embargo, se desconocen los cambios de estos compuestos en variedades blancas de los cultivos colombianos como Guavatá Victoria (GV), Regional Blanca (RB) y Ráquira (RQ). Se utilizó el método Headspace-Microextracción en Fase Sólida (HS-MEFS) para comparar los perfiles olfativos de tres variedades de guayaba blanca de la región de la hoya del río Suárez (Santander, Colombia) durante tres etapas de maduración (verde, pintón y maduro). En las tres variedades se presentó un comportamiento similar, los aldehidos C-6 (hexanal, (Z)-3-hexenal y (E)-2-hexenal) responsables de la nota verde disminuyen durante la maduración, mientras que el contenido de ésteres (acetato de hexilo y acetato de (Z)-3-hexenilo) aumenta produciéndose las notas dulce y frutal características de la fruta madura. Los compuestos ácidos, furánicos y alcoholes se observan en bajas proporciones durante las tres etapas. El análisis de los compuestos volátiles mediante HS-MEFS permitió establecer una relación entre la transformación de compuestos aldehídos C6, responsables de la nota verde, en ésteres análogos, a los cuales se les atribuye la nota frutal característica durante el proceso de maduración.
The composition of volatile compounds during guava ripening (Psidium guajava L.) has been an aspect broadly studied. However, the changes of these compounds in representative white varieties from Colombia, like Guavatá Victoria (GV), Regional Blanca (RB) and Ráquira (RQ) are still unknown. Comparison of the aroma profiles was done using heads-pace-Solid Phase Micro Extraction (HS-SPME) for three white guava varieties from the Suárez River Basin region (Santander, Colombia) during three maturation stages (green, half-ripened and ripen). The three varieties presented a similar behavior, the C6- aldehydes (hexanal, (Z)-3-hexenal and (E)-2-hexenal) characterized for a green note diminished during ripening, while ester amounts (hexyl acetate and (Z)-3-hexenyl acetate) increase, producing sweet and fruity notes characteristics in a ripen fruit. The acids, furanics and alcohol compounds are present in low proportions at the three stages. Through HS-SPME analysis, we established a relation between C6-aldehy-des compounds transformation, responsible of the green note, into analogue esters that contribute to the fruity note during the ripening process.
A formação dos compostos voláteis durante o processo de amadurecimento da goiaba (Psidium guajava L.) tem sido muito estudada. Entretanto, pouco se conhece sobre as mudanças desses compostos nas variedades brancas representadas pela Guavatá Victoria (GV), Regional Blanca (RB) e Ráquira (RQ) na região do rio Suárez (Santander-Colômbia). O emprego da técnica HS-MEFS (Heads-pace-Microextração em fase sólida) para comparar o perfil olfativo durante as etapas da maturação (verde, semimaduro e maduro) mostrou um comportamento similar nas três variedades de goiaba branca: os aldeídos C-6 (hexanal, (Z)-3-hexe-nal e (E)-2-hexenal), caracterizados por uma nota verde, diminuíram ao longo do amadurecimento, enquanto que o conteúdo de ésteres (acetato de hexilo e acetato de (Z)-3-hexenilo) aumentou, produzindo as notas doces e frutal caracteristicas da fruta madura. Os compostos ácidos, furânicos e alcoólicos foram observados em baixas concentrações nas três etapas de maturação. Por fim, a técnica HS-MEFS permitiu detectar a rápida transformação dos compostos aldeídos C6, causadores da nota verde em ésteres análogos que causam a nota frutal durante o processo da maturação.