Effects of shade treatments on photosynthetic characteristics, chloroplast ultrastructure, and physiology of Anoectochilus roxburghii.

Anoectochilus roxburghii was grown under different shade treatments-50%, 30%, 20%, and 5% of natural irradiance-to evaluate its photosynthetic characteristics, chloroplast ultrastructure, and physiology. The highest net photosynthetic rates and stomatal conductance were observed under 30% irradiance, followed in descending order by 20%, 5%, and 50% treatments. As irradiance decreased from 50% to 30%, electron transport rate and photochemical quenching increased, while non-photochemical quenching indexes declined. Reductions in irradiance significantly increased Chl a and Chl b contents and decreased Chl a/b ratios. Chloroplast ultrastructure generally displayed the best development in leaves subjected to 30% irradiance. Under 50% irradiance, leaf protein content remained relatively stable during the first 20 days of treatment, and then increased rapidly. The highest peroxidase and superoxide dismutase levels, and the lowest catalase activities, were observed in plants subjected to the 50% irradiance treatment. Soluble sugar and malondialdehyde contents were positively correlated with irradiance levels. Modulation of chloroplast development, accomplished by increasing the number of thylakoids and grana containing photosynthetic pigments, is an important shade tolerance mechanism in A. roxburghii

Gut microbiota and transcriptome profiling revealed the protective effect of aqueous extract of Tetrastigma hemsleyanum leaves on ulcerative colitis in mice

Tetrastigma hemsleyanum, a traditional Chinese medicinal plant, possesses various biological activities, including anti-inflammatory and immunomodulatory functions. The purpose of this study was to determine the alleviating effect of the water extract of Tetrastigma hemsleyanum leaves (THLW) on ulcerative colitis (UC) and its relationship with gut microbiota. The administration of THLW significantly decreased the severity of dextran sulfate sodium (DSS)-induced intestinal damage, as demonstrated by the stabilization of body weight and colon length, and decreased disease activity index (DAI) and histological scores. THLW also decreased NF-κB protein expression in colon tissues and reduced the serum levels of IL-6, IL-1β, and TNF-α. Further co-housing experiment confirmed that the anti-UC effect of THLW was possibly by regulating the structure and composition of gut microbiota, including increasing the abundance of Oscillospiraceae, Prevotellaceae and Corynebacterium. Additionally, the expression of genes related to inflammation and immunity was also regulated by THLW treatment as evidenced by transcriptome analysis. These results suggested that the protective effect of THLW on DSS-induced colitis was mediated by alleviating inflammation and modulating the microbiota composition. This work proved the potent protective effects of THLW treatment on colitis and may have potential for UC relief

Exogenous spermidine enhanced the water deficit tolerance of Anoectochilus roxburghii by modulating plant antioxidant enzymes and polyamine metabolism

Water stress is an important factor affecting herb quality and yield and exogenous spermidine (Spd) addition can enhance dehydration tolerance of plants. Anoectochilus roxburghii (Wall.) Lindl is a perennial herb widely used in medicine, health care, and beauty industry, yet, its dehydration resistance remains largely unknown. In this view, the current research aimed at elucidating the drought resistance mechanism of A. roxburghii under PEG-induced water stress at different levels (10%, 20%, and 30% PEG6000). In particular, the morphological, physiological, and biochemical changes occurring in leaves treated with (0.5 mM, 5 mM) or without Spd were discussed under moderate water stress (20% PEG6000). Results showed that water stress significantly inhibited the growth of A. roxburghii by decreasing the activities of superoxide dismutase (SOD), peroxidase (POD), catalase (CAT), arginine decarboxylase (ADC), S-adenosylmethionine decarboxylase (SAMDC), and polyamine oxidase (PAO). The contents of soluble protein, soluble proline, hydrogen peroxide (H2O2), malondialdehyde (MDA), and the relative conductivity (REC) of leaves increased by 27.32%, 31.37%, 68.84%, 103.61%, and 63.64%, respectively. Under dehydration condition, foliar spraying Spd effectively improved plant growth with the contents of soluble protein and soluble proline increased, while the H2O2, REC, and MDA contents decreased. The SOD activity of 0.5 mM and 5 mM treatments were 1.13 and 1.01 times higher than only 20% PEG treatment, respectively. Similarly, the POD activity of 0.5 mM and 5 mM treatments increased by 52.82% and 34.11%, while the CAT activity of 0.5 mM and 5 mM treatments increased by 34.39 and 33.15 U/mgprot, respectively. In addition, exogenous Spd application significantly increased the key enzyme activities of polyamine metabolism (ADC, SAMDC, and PAO) under moderate water stress. In conclusion, exogenous Spd addition with low concentration (0.5 mM) improved the resistance of A. roxburghii against water stress by increasing the antioxidant enzymes activities and endogenous polyamines contents. This study helps to the understanding of dehydration resistance of A. roxburghii and provide guidelines for its cultivation under water deficit condition

Molecular characterization and evolutionary history analysis of a novel Kudzu mosaic virus (KMV) infecting the Kudzu (Pueraria montana)

Objectives: Plant viruses are a significant contributor to the economic losses experienced in numerous plant species. Begomoviruses exhibit a wide range of host species, encompassing both cultivated and non-cultivated plants. The kudzu plant, scientifically known as Pueraria montana, is indigenous to the Southeast Asian region. Moreover, it exhibits varied attributes with regards to its utilization in the fields of medicine, food, cosmetics, and the herbal industry. Methods: During a routine survey, some P. montana plants having typical symptoms of yellowing, mosaic, and mottle were observed in areas including Fort-Minro (FM) and Anari of district Dera Ghazi Khan and Maari (MA) of district Rajanpur. The genomic DNA was extracted from the collected samples. The polymerase chain reaction (PCR) and rolling circular amplification (RCA) was carried out to isolate the DNA and DNA- β from the collected plant specimens. An evolutionary research was conducted to assess the lineage of this virus inside a novel geographical region. Results: A 500-bp amplicon size was obtained from the samples of the FM and MA, while the approximately 2.7-kb amplicon size of its full genome was obtained from the samples of both locations. The results of the sequence analysis demonstrated conclusively that the plants in question are infected with Kudzu mosaic virus (KMV). The evolutionary history analysis has confirmed the virus's lineage in a new region, and the nucleotide frequencies of obtained sequences were variable. Conclusion: The presence of a novel bipartite begomovirus in the tropical region has been substantiated using a phylogenetic and evolutionary investigation. The observation of a white fly population on infected plants has also suggested that the transmission of this virus through the migration of this insect vector can be a viable mechanism

Protein content (a), POD activity (b), SOD activity (c), CAT activity (d), Soluble sugar content (e) and MDA content (f).

<p>Protein content (a), POD activity (b), SOD activity (c), CAT activity (d), Soluble sugar content (e) and MDA content (f).</p

Curves of diurnal variation of photosynthetically active radiation (PAR) under 50%, 30%, 20% and 5% light irradiances during one day in June 2012 in Lin’an, China.

<p>Curves of diurnal variation of photosynthetically active radiation (PAR) under 50%, 30%, 20% and 5% light irradiances during one day in June 2012 in Lin’an, China.</p

The Chl a content (a), Chl b content (b), Chl a+b content (c) and Chl a/b (d).

<p>The values represented mean ± SE, and different letters mark significant differences among shade treatments on the same day (P<0.05).</p

Net photosynthetic rate (P_n) (a), stomatal conductance (G_s) (b) and intercellular CO₂ concentration (C_i) (c).

<p>The values represented mean ± SE, and different letters mark significant differences among shade treatments on the same day (P<0.05).</p

The chloroplast ultrastructure observed in the leaves of Anoectochilus roxburghii at 40 DOT.

<p>(a), (b), (c) the plants under 50% irradiance treatment; (d), (e), (f) the plants under 30% irradiance treatment; (g), (h), (i) the plants under 20% irradiance treatment; (j), (k), (l) the plants under 5% irradiance treatment. Notice the differences of the number of SG (indicated by arrow heads) and the number of grana lamella (indicated by arrows) between different irradiances. Abbreviation: Ch, chloroplast; CW, cell wall; OG, osmiophilic globules.</p

The appearance of whole plants (a) and leaves (b) exposed to 40 d of various levels of shading.

<p>The appearance of whole plants (a) and leaves (b) exposed to 40 d of various levels of shading.</p