As important decomposers and plant symbionts, soil fungal communities play a major role in remediating heavy-metal-polluted soils. However, the diversity and structures of fungal communities generally remain unclear in mining areas. This study aimed to assess the rhizospheric fungal-community composition of Masson pine (Pinus massoniana) in the lead-zinc mining area of Suxian District, Hunan Province, China. This experiment undertook the following three treatments: Masson pine inoculated with or not inoculated with Suillus luteus, and bulk soil without plants as a control. The results thereof showed that inoculation of ectomycorrhizal fungi could enlarge plants’ capability to absorb heavy metals and secrete soil enzymes. The richness and diversity of fungi in the rhizospheric soil were significantly higher than of those in the bulk soil (p < 0.05), but no significant difference was noted between the rhizospheric soils inoculated with and not inoculated with ectomycorrhizal (ECM) fungi as the community structure changed. The rhizospheric fungi belonged to 6 phyla, 25 classes, 65 orders, 115 families, and 150 genera, and the dominant phyla were Chytridiomycota (50.49%), Ascomycota (38.54%), and Basidiomycota (9.02%). Through use of LEfSe and heatmapping, the relative abundances of Suillus, Paraglomus, Agaricus, and Tulasnella were found to be the highest in the soil with ECM fungus inoculation. RDA showed that the community structure nearly changed with ECM-fungus inoculation; this was significantly related to soil water content, the carbon–nitrogen ratio, bulk density, available potassium, and soil enzymes. Altogether, inoculation with ECM fungi may change the habitation environments of microorganisms and dominant fungi in soil, providing keystone screenings in heavy-metal-contaminated mining areas.

Zinc (Zn) is a widespread industrial pollutant that causes detrimental effects to plant growth and development. Photoprotective properties ensure plant survival during stress by protecting the photosynthetic apparatus. This occurs via numerous mechanisms, including non-photochemical quenching (NPQ), cyclic electron flow (CEF), and the water-to-water cycle (WWC). However, whether and how Zn stress affects the photoprotective properties of plants to enhance tolerance of Zn toxicity remains unknown. In this study, we treated Melia azedarach plants with different Zn concentrations ranging from 200 to 1,000 mg Kg⁻¹. We then analyzed the activities of two leaf photosynthetic pigment components—photosystems I and II (PSI and PSII) and the relative expression levels of their subunit genes. As expected, we found that Zn treatment decreases photosynthesis and increases photodamage in M. azedarach leaves. Zn treatments exacerbated a variety of photodamage phenotypes in photosystem activities and altered the expression levels of key photosystem complex genes and proteins. Furthermore, our results demonstrated that PSI was more seriously damaged than PSII under Zn stress. Subsequently, we compared differences in photodamage in the NPQ, CEF, and WWC photoprotection pathways under Zn stress and found that each exerted a protective function again photodamage under 200 mg Kg⁻¹ Zn stress. NPQ and CEF may also play major protective roles to avoid irreversible photodamage and ensure survival under higher (i.e., 500 and 1,000 mg Kg⁻¹) levels of Zn stress. Thus, our study revealed that NPQ- and CEF-based photoprotection mechanisms are more effective than WWC in M. azedarach upon Zn stress.

In vitro anther culture is a technique used to produce haploid plants when regenerating varieties with specific traits. To generate haploid plants with preferred characteristics, an anther culture technique was established for Lilium longiflorum “Show Up”. Morphological characteristics were recorded, including the flower bud length and anther color corresponding to different stages of microspore development. The effects of different flower bud lengths, various concentrations of exogenous plant growth regulators (PGRs), low-temperature pretreatment at 4 °C, and incubation under dark conditions on the induction of callus formation were studied. When the flower buds were 2.2–2.4 cm in length and the microspores were in the mononuclear development phase, callus induction reached the highest rate (15.6%). Callus was not induced when the PGRs 2,4-dichlorophenoxyacetic acid (2,4-D) and kinetin (KT) were added separately to the growth medium, but the highest callus induction rate occurred when anthers were cultured on the medium containing 2,4-D (0.75–1.0 mg/L) and KT (4 mg/L). The low-temperature pretreatment significantly enhanced the induction rate of anthers, but prolonged low-temperature pretreatment reduced the induction rate. The optimal period of cultivation in darkness was 6 d. After 15 days of cultivation, the number of swollen anthers was recorded, and these were transferred onto the differentiation medium Murashige and Skoog (MS) + 1-naphthaleneacetic acid (NAA) (2.0 mg/L), sucrose (30 g/L), and agar (7 g/L) at pH 5.8, whereon 100% differentiation was recorded. Overall, 14 regenerated lines were obtained by in vitro anther culture. Chromosome ploidy was determined by counting chromosomes in the root tips of ten regenerated plants, and four were found to be haploids. This study lays the foundation for anther culture in lilies to shorten the breeding cycle, improve selection efficiency, facilitate efficient genetic transformation, and enable the effective production of both haploid and double-haploid plants.

Global warming-induced heat stress increasingly threatens the ornamental quality and productivity of roses. Previous studies have indicated that trehalose and the trehalose-6-phosphate synthase (TPS) gene family regulate plants' stress resistance, yet their roles in thermotolerance in rose remain uncharacterized. We previously identified RcTPS7b as a putative heat-responsive gene in Rosa chinensis 'Slater's Crimson China'. This study aimed to investigate whether exogenous trehalose enhances heat tolerance in rose, and elucidate the functional role of RcTPS7b in heat stress regulation. The results showed that exogenous application of 5 mmol/L trehalose significantly enhanced rose's heat tolerance by reducing the heat damage index, elevating superoxide dismutase (SOD) activity, and preserving the efficiency of Photosystem II (PSII). Overexpression of RcTPS7b in Arabidopsis thaliana enhanced the heat tolerance and antioxidant enzyme activities in transgenic plants, concomitant with upregulated expression of heat-resistant genes such as HEAT SHOCK FACTOR/PROTEIN (AtHSF/P). Furthermore, tobacco rattle virus-induced silencing of RcTPS7b in R. chinensis compromised thermotolerance and induced severe oxidative damage. Transient overexpression of RcTPS7b in rose petals reduced heat damage and maintained petal integrity through redox homeostasis under high temperature treatment. Collectively, this study demonstrates that exogenous trehalose potentiates RcTPS7b expression to enhance thermotolerance, revealing the trehalose metabolism pathway's pivotal role in heat stress regulation in R. chinensis, and will be helpful for the molecular breeding of heat tolerance in R. chinensis.