A long and stressful day: Photoperiod shapes aluminium tolerance in plants

The Modulation of Growth and Metabolism in Solanum lycopersicum Contrast With the Leaf-Specific Regulation of Wild Tomato Species

Plant organs harbour diverse components that connect their physiology to the whole organism. The turnover of metabolites may be higher in some organs than in others, triggering differential growth patterns throughout the organism. We revealed that Solanum lycopersicum exhibits more coordinated growth and physiology across the entire plant compared to wild tomato species. Specifically, young leaves of S. lycopersicum develop more slowly than mature leaves, whereas wild species do not exhibit this pattern. Wild tomato Solanum pennellii displays young leaves with higher photosynthetic rates than mature leaves. Consequently, sucrose metabolism in S. pennellii is quite similar between young and mature leaves, while expression patterns of circadian clock genes differ significantly between leaves of different ages. Additionally, we demonstrated that introducing alleles related to tomato domestication into the wild tomato Solanum pimpinellifolium promotes coordinated growth between young and mature leaves, resulting in similar patterns to those observed in S. lycopersicum. Collectively, S. lycopersicum appears to exhibit more coordinated regulation of growth and metabolism, and understanding this process is likely fundamental to explaining its elevated harvest index.

Multiomics and biotechnologies for understanding and influencing cadmium accumulation and stress response in plants

Cadmium (Cd) is one of the most toxic heavy metals faced by plants and, additionally, via the food chain, threatens human health. It is principally dispersed through agro-ecosystems via anthropogenic activities and geogenic sources. Given its high mobility and persistence, Cd, although not required, can be readily assimilated by plants thereby posing a threat to plant growth and productivity as well as animal and human health. Thus, breeding crop plants in which the edible parts contain low to zero Cd as safe food stuffs and harvesting shoots of high Cd-containing plants as a route for decontaminating soils are vital strategies to cope with this problem. Recently, multiomics approaches have been employed to considerably enhance our understanding of the mechanisms underlying (i) Cd toxicity, (ii) Cd accumulation, (iii) Cd detoxification and (iv) Cd acquisition tolerance in plants. This information can be deployed in the development of the biotechnological tools for developing plants with modulated Cd tolerance and detoxification to safeguard cellular and genetic integrity as well as to minimize food chain contamination. The aim of this review is to provide a current update about the mechanisms involved in Cd uptake by plants and the recent developments in the area of multiomics approach in terms of Cd stress responses, as well as in the development of Cd tolerant and low Cd accumulating crops.

Two-for-one: root microbiota orchestrates both soil pH and plant nutrition

Aluminum (Al) toxicity is a crucial limiting factor for crop growth in acid soils. Recently, Liu et al. demonstrated that the root microbiota of rice modulates the responses to Al toxicity and phosphorus limitation, offering intriguing insights into microbiome function and opening new research opportunities.

Remediation of the microecological environment of heavy metal-contaminated soil with fulvic acid, improves the quality and yield of apple

The excessive application of chemical fertilizers and pesticides in apple orchards is responsible for high levels of manganese and copper in soil, and this poses a serious threat to soil health. We conducted a three-year field experiment to study the remediation effect and mechanism of fulvic acid on soil with excess manganese and copper. The exogenous application of fulvic acid significantly reduced the content of manganese and copper in soil and plants; increased the content of calcium; promoted the growth of apple plants; improved the fruit quality and yield of apple; increased the content of chlorophyll; increased the activity of superoxide dismutase, peroxidase, and catalase; and reduced the content of malondialdehyde. The number of soil culturable microorganisms, soil enzyme activity, soil microbial community diversity, and relative abundance of functional bacteria were increased, and the detoxification of the glutathione metabolism function was enhanced. The results of this study provide new insights that will aid the remediation of soil with excess manganese and copper using fulvic acid.

Does day length matter for nutrient responsiveness?

For over 2500 years, considerable agronomic interest has been paid to soil fertility. Both crop domestication and the Green Revolution shifted photoperiodism and the circadian clock in cultivated species, although this contributed to an increase in the demand for chemical fertilisers. Thus, the uptake of nutrients depends on light signalling, whereas diel growth and circadian rhythms are affected by nutrient levels. Here, we argue that day length and circadian rhythms may be central regulators of the uptake and usage of nutrients, also modulating responses to toxic elements (e.g., aluminium and cadmium). Thus, we suggest that knowledge in this area might assist in developing next-generation crops with improved uptake and use efficiency of nutrients.

The Role of TCA Cycle Enzymes in Plants

As one of the iconic pathways in plant metabolism, the tricarboxylic acid (TCA) cycle is commonly thought to not only be responsible for the oxidization of respiratory substrate to drive ATP synthesis but also provide carbon skeletons to anabolic processes and contribute to carbon-nitrogen interaction and biotic stress responses. The functions of the TCA cycle enzymes are characterized by a saturation transgenesis approach, whereby the constituent expression of proteins is knocked out or reduced in order to investigate their function in vivo. The alteration of TCA cycle enzyme expression results in changed plant growth and photosynthesis under controlled conditions. Moreover, improvements in plant performance and postharvest properties are reported by overexpression of either endogenous forms or heterologous genes of a number of the enzymes. Given the importance of the TCA cycle in plant metabolism regulation, here, the function of each enzyme and its roles in different tissues are discussed. This article additionally highlights the recent finding that the plant TCA cycle, like that of mammals and microbes, dynamically assembles functional substrate channels or metabolons and discusses the implications of this finding to the current understanding of the metabolic regulation of the plant TCA cycle.

Circadian Rhythm Regulates Reactive Oxygen Species Production and Inhibits Al-Induced Programmed Cell Death in Peanut

Peanut is among the most important oil crops in the world. In the southern part of China, peanut is highly produced; however, the arable land is acidic. In acidic soils, aluminum (Al) inhibits plant growth and development by changing the properties of the cell wall and causing the disorder of the intracellular metabolic process. Circadian rhythm is an internal mechanism that occurs about every 24 h and enables plants to maintain internal biological processes with a daily cycle. To investigate the effect of photoperiod and Al stress on the Al-induced programmed cell death (PCD), two peanut varieties were treated with 100 μM AlCl₃ under three photoperiodic conditions (8/16, SD; 12/12, ND; 16/8 h, LD). The results show that Al toxicity was higher in ZH2 than in 99-1507 and higher under LD than under SD. Root length decreased by 30, 37.5, and 50% in ZH2 and decreased by 26.08, 34.78, and 47.82% in 99-1507 under SD, ND, and LD, respectively, under Al stress. Photoperiod and Al induced cell death and ROS production. MDA content, PME activity, and LOX activity increased under SD, ND, and LD, respectively, under Al stress both in ZH2 and 99-1507. APX, SOD, CAT, and POD activities were higher under SD, ND, and LD, respectively. Al stress increased the level of AhLHY expression under SD and ND but decreased it under LD in both ZH2 and 99-1507. Contrastingly, AhSTS expression levels increased exponentially and were higher under SD, LD, and ND, respectively, under Al stress. Our results will be a useful platform to research PCD induced by Al and gain new insights into the genetic manipulation of the circadian clock for plant stress response.