Physiological, nutritional, and molecular responses of Brazilian sugarcane cultivars under stress by aluminum

Abstract

Background Sugarcane is a crop of global importance and has been expanding to areas with soils containing high levels of exchangeable aluminum (Al), which is a limiting factor for crop development in acidic soils. The study of the sugarcane physiological and nutritional behavior together with patterns of gene expression in response to Al stress may provide a basis for effective strategies to increase crop productivity in acidic soils. Methods Sugarcane cultivars were evaluated for physiological parameters (photosynthesis, stomatal conductance, and transpiration), nutrient (N, P, K, Ca, Mg, and S) and Al contents in leaves and roots and gene expression, of the genes MDH, SDH by qPCR, both related to the production of organic acids, and SOD, related to oxidative stress. Results Brazilian sugarcane RB867515, RB928064, and RB935744 cultivars exhibited very different responses to induced stress by Al. Exposure to Al caused up-regulation (SOD and MDH) or down-regulation (SDH, MDH, and SOD), depending on the cultivar, Al level, and plant tissue. The RB867515 cultivar was the most Al-tolerant, showing no decline of nutrient content in plant tissue, photosynthesis, transpiration, and stomatal conductance after exposure to Al; it exhibited the highest Al content in the roots, and showed important MDH and SOD gene expression in the roots. RB928064 only showed low expression of SOD in roots and leaves, while RB935744 showed important expression of the SOD gene only in the leaves. Sugarcane cultivars were classified in the following descending Al-tolerance order: RB867515 > RB928064 = RB935744. These results may contribute to the obtention of Al-tolerant cultivars that can play their genetic potential in soils of low fertility and with low demand for agricultural inputs; the selection of potential plants for breeding programs; the elucidation of Al detoxification mechanisms employed by sugarcane cultivars.

EFECTOS BIOESTIMULANTES DEL ALUMINIO EN CRECIMIENTO Y METABOLISMO DE CAÑA DE AZÚCAR in vitro

“…El mismo fenómeno fue observado en plantas de baya-zafiro (Schmitt et al, 2016). En variedades de caña de azúcar también se han reportado diferentes respuestas y capacidad de adaptación a la presencia de Al 3+ (Oliveira et al, 2021). Si bien la resistencia a Al 3+ se ha investigado en los principales cultivos, los mecanismos precisos que llevan al desarrollo de tales respuestas a nivel bioquímico y molecular no han sido elucidados en su totalidad.…”

“…Estos resultados ponen en evidencia que el tratamiento con Al 3+ en concentraciones de 50 y 100 µM influye positivamente en las concentraciones foliares de clorofilas, moléculas determinantes en la fotosíntesis y por ende en el crecimiento y desarrollo de la planta. En condiciones de estrés hídrico y salino, las concentraciones de clorofilas pueden incrementarse en diversas hortalizas (Bulgari et al, 2019); sin embargo, cuando el Al 3+ se suministra fuera del rango hormético, el aparato fotosintético puede ser irrumpido, lo que causa una disminución en la concentración y alteración en las estructuras de clorofilas y del fotosistema II, cierre de los centros de reacción (RCS) e inhibición del transporte de electrones (Negreanu-Pirjol et al, 2019;Oliveira et al, 2021). En frijol común, si bien la aplicación de 50 µM Al 3+ por 72 h no tuvo efectos en las concentraciones de clorofilas, al aumentar la dosis y el tiempo de exposición, se observaron efectos fitotóxicos (Chico et al, 2021).…”

Evaluation of sugarcane promising clones based on the morphophysiological traits developed from fuzz

“…Furthermore, sugarcane is important for the environment because it is a C4 plant with high photosynthetic efficiency and requires less water and nitrogen compared to other crops. It can also sequester carbon in the soil, making it an important tool for mitigating climate change ( Budeguer et al, 2021 ; de Souza Oliveira et al, 2021 ). Sugarcane production in Pakistan is hindered by several biotic and abiotic factors, including temperature, humidity, lack of technology implementation, a complicated genome, a low fertility rate, a long selection of breeding cycles, an unfavorable day length during the flowering period, and a poor seed setting rate in ordinary environments ( Sanghera et al, 2019 ).…”