Plant root systems play a fundamental role in nutrient and water acquisition. In resource‐limited soils, modification of root system architecture is an important strategy to optimize plant performance. Most terrestrial plants also form symbiotic associations with arbuscular mycorrhizal fungi to maximize nutrient uptake. In addition to direct delivery of nutrients, arbuscular mycorrhizal fungi benefit the plant host by promoting root growth. Here, we aimed to quantify the impact of arbuscular mycorrhizal symbiosis on root growth and nutrient uptake in maize. Inoculated plants showed an increase in both biomass and the total content of twenty quantified elements. In addition, image analysis showed mycorrhizal plants to have denser, more branched root systems. For most of the quantified elements, the increase in content in mycorrhizal plants was proportional to root and overall plant growth. However, the increase in boron, calcium, magnesium, phosphorus, sulfur, and strontium was greater than predicted by root system size alone, indicating fungal delivery to be supplementing root uptake.

Grafting generally means stress to a plant and this triggers antioxidant defense systems. An imbalance in reactive oxygen species may negatively affect the grafting success. Several research projects have studied the association with plant growth-promoting rhizobacteria (PGPR) and it has been documented that they enhance nutrient acquisition, regulate hormone levels, and influence the antioxidant response in crops. However, little is known about the strategy of inoculating grafted herbaceous plants with PGPR and its effect on the antioxidant response. The effects of inoculating a strain of Bacillus subtilis on the antioxidant metabolism of grafted tomato were evaluated. In this study, two different rootstocks were used for tomato (Solanum lycopersicum L. var. Rio Grande (RG)): [S. lycopersicum L. var. cerasiforme (Ch)] and eggplant [(Solanum melanogena L. (Ber)] to establish a compatible graft (RGCh) and a semicompatible graft (RGBer). Enzyme activities involved in the antioxidant defense system: superoxide dismutase (SOD), catalase (CAT), phenylalanine ammonia lyase (PAL), polyphenol oxidase (PPO), peroxidase (POD), and total phenols were measured during 4 weeks after grafting. The results show that for RGCh, during the first two weeks after grafting, the tendency was a decrease of the enzyme activity for SOD, CAT, PAL when inoculated with B. subtilis; while in the semicompatible graft RGBer, PPO and PAL decreased their activity after inoculation. For both combinations, the quantity of total phenols varied depending on the day. In both graft combinations, applications of B. subtilis resulted in 86 and 80% callusing compared with the uninoculated control where the percentages were 74 and 70% for RGCh and RGBer, respectively. The highest significant graft success (95%) was recorded 28 days after grafting for inoculated RGBer. These findings imply that B. subtilis induced antioxidant mechanisms in grafted plants and suggest that inoculation with this growth-promoting bacterium can represent a biotechnological approach to improve success in tomato grafting.

Neopestalotiopsis spp. are emerging fungal pathogens associated with leaf spot, fruit rot, crown rot, and root rot in strawberries. Despite their endophytic lifestyle, global outbreaks of these pathogens have been reported over the past few years, causing severe economic losses in commercial strawberry production. Resistance has been reported against the chemical fungicides used to manage Neopestalotiopsis spp. This review comprehensively examines the epidemiology, biology, and infection mechanisms of Neopestalotiopsis spp. on strawberries. Recent advances in management strategies, including biological control agents and resistant strawberry cultivars, have also been highlighted. By integrating these approaches, this work aims to provide a foundation for sustainable management practices to mitigate the impact of Neopestalotiopsis spp. on strawberry production.

Arbuscular mycorrhizal fungi (AMF) establish symbioses with the major cereal crops, providing plants with increased access to nutrients while enhancing their tolerance to toxic heavy metals. However, not all plant varieties benefit equally from this association. In this study, we used quantitative trait loci (QTL) mapping to evaluate the combined effect of host genotypic variation (G) and AMF across 141 genotypes on the concentration of 20 mineral elements in the leaves and grain of field grown maize (Zea mays spp. mays). Our mapping design included selective incorporation of a castor AMF-incompatibility mutation, allowing estimation of AMF, QTL and QTLxAMF effects by comparison of mycorrhizal and non-mycorrhizal plants. Overall, AMF compatibility was associated with higher concentrations of boron (B), copper (Cu), molybdenum (Mo), phosphorus (P), selenium (Se) and zinc (Zn) and lower concentrations of arsenic (As), iron (Fe), magnesium (Mg), manganese (Mn), potassium (K) and strontium (Sr). In addition to effects on individual elements, pairwise correlation matrices for element concentration differed between mycorrhizal and non-mycorrhizal plants. We mapped 22 element QTLs, including 18 associated with QTLxAMF effects that indicate plant genotype-specific differences in the impact of AMF on the host ionome. Although there is considerable interest in AMF as biofertilizers, it remains challenging to estimate the impact of AMF in the field. Our design illustrates an effective approach for field evaluation of AMF effects. Furthermore, we demonstrate the capacity of the ionome to reveal host genotype-specific variation in the impact of AMF on plant nutrition.