Herbivory and leaf expansion of Cyathea phalerata Mart. (Cyatheaceae) in subtropical Atlantic Forest, southern Brazil

Herbivory is an interaction with great impact on plant communities since relationships between herbivores and plants are fundamental to the distribution and abundance of species over time and space. The aim of this study was to monitor the rate of leaf expansion in the tree fern Cyathea phalerata and evaluate the damage caused by herbivores to leaves of different ages and whether such damage is related to temperature and precipitation. The study was performed in a subtropical Atlantic Forest fragment located in the municipality of Caraá, in the northeast hillside of Rio Grande do Sul state, in southern Brazil. We monitored 24 mature individuals of C. phalerata with croziers in a population of approximately 50 plants. Leaf expansion rate, percentage of damaged leaves and leaf blade consumption rate by herbivory were calculated. Monthly means for temperature and accumulated rainfall were calculated from daily data. Croziers of C. phalerata were found to expand rapidly during the first and second months after emergence (3.98 cm day-1; 2.91 cm day-1, respectively). Damage caused by herbivory was observed in all of the monitored leaves, but none of the plants experienced complete defoliation. The highest percentage (57%) of damaged leaves was recorded at 60 days of monitoring, and also the highest monthly consumption rate of the blade (6.04%) occurred with young, newly-expanded leaves, while this rate remained between 1.50 and 2.21% for mature leaves. Rates of monthly leaf consumption and damaged leaves showed positive and strong relationship with each other and with temperature. The rapid leaf expansion observed for C. phalerata can be considered a phenological strategy to reduce damage to young leaves by shortening the developmental period and accelerating the increase of defenses in mature leaves.

Inheritance of seedlessness and the molecular characterization of the INO gene in Annonaceae

The inheritance of the seedless fruit characteristic of Annona squamosa has not yet been explained. Molecular techniques may aid breeding programs, mainly in the assisted selection of the target gene. The INO gene may be related to seed development in these fruits. The objective of the present paper was to investigate the inheritance of seedlessness in the 'Brazilian seedless' sugar apple and INO gene conservation in Annona squamosa and Annona cherimola x Annona squamosa genotypes by assessing their homology with the INO database genes. The F1 generation was obtained by crossing the mutant 'Brazilian seedless' (male genitor) (P1) with the wild-type A. squamosa with seeds (M1 and M2, female genitors). The INO gene was studied in mutant and wild-type A. squamosa (P1, M1, M2 and M3) and in the Gefner atemoya (A. cherimola x A. squamosa) (M4) cultivar. The DNA was extracted from young leaves, and four sets of specific primers flanking the INO gene were amplified. The seedless characteristic was identified as stenospermatic in the fruits of parental P1, suggesting monogenic inheritance with complete dominance. High sequence similarity of the INO gene amplifications in the sugar apple accessions (M1, M2, M3) and the atemoya cultivar Gefner (M4) reinforces the hypothesis of their conservation.

The effects of pH, salinity, age of leaves, post-harvest storage duration, and psyllid infestation on nutritional qualities of giant leucaena fodder

Giant leucaena (Leucaena leucocephala subsp. glabrata) can be managed as a profusely branched bushy plant by repeated harvest of its foliage for use as fodder. The objective of this research was to determine the effects of soil pH and salinity, age of the leaves, post-harvest storage duration, and psyllid infection on the nutritional qualities of leucaena fodder. To determine the effects of soil pH and salinity on fodder quality, giant leucaena K636 plants were grown in large pots containing soils adjusted to different pH and salinity levels. The effects of age of the leaves, post-harvest storage duration and psyllid infection on fodder quality were studied using leucaena samples collected from Waimanalo Research Station. Among five pH levels tested, pH 6.0 was found to produce the highest amounts of protein and structural fibers in the foliage. Mimosine contents were highest at pH 6 and 7 and lowest at pH 5.0. The growth of giant leucaena was retarded and the nutritional quality were adversely affected under salinity conditions. Compared to young leaves, old leaves contained 18.5% less protein, 95% less mimosine, 30% less tannin and 40% more structural fibers. Post-harvest storage duration up to 72 h, at room temperature did not seem to affect protein, tannin and structural fiber contents of the foliage; however, mimosine content was reduced by 25%. These results will help to identify ideal soil pH, age of foliage, and post-harvest storage duration for obtaining high forage yield and nutritional quality for giant leucaena.

Regulation of Leaf Angle Protects Photosystem I under Fluctuating Light in Tobacco Young Leaves

Fluctuating light is a typical light condition in nature and can cause selective photodamage to photosystem I (PSI). The sensitivity of PSI to fluctuating light is influenced by the amplitude of low/high light intensity. Tobacco mature leaves are tended to be horizontal to maximize the light absorption and photosynthesis, but young leaves are usually vertical to diminish the light absorption. Therefore, we tested the hypothesis that such regulation of the leaf angle in young leaves might protect PSI against photoinhibition under fluctuating light. We found that, upon a sudden increase in illumination, PSI was over-reduced in extreme young leaves but was oxidized in mature leaves. After fluctuating light treatment, such PSI over-reduction aggravated PSI photoinhibition in young leaves. Furthermore, the leaf angle was tightly correlated to the extent of PSI photoinhibition induced by fluctuating light. Therefore, vertical young leaves are more susceptible to PSI photoinhibition than horizontal mature leaves when exposed to the same fluctuating light. In young leaves, the vertical leaf angle decreased the light absorption and thus lowered the amplitude of low/high light intensity. Therefore, the regulation of the leaf angle was found for the first time as an important strategy used by young leaves to protect PSI against photoinhibition under fluctuating light. To our knowledge, we show here new insight into the photoprotection for PSI under fluctuating light in nature.

Effects of homoeologous exchange on gene expression and alternative splicing in a newly formed allotetraploid wheat

Homoeologous exchange (HE) is a major mechanism generating post-polyploidization genetic variation with important evolutionary consequences. However, the direct impacts of HE without entangling with additional evolutionary forces on gene expression remains to be fully understood. Here, we analyzed high-throughput RNA-seq data of young leaves from individuals of a synthetic allotetraploid wheat (AADD), which contain variable numbers of HEs. We aimed to investigate if and to which extent HE directly impacts gene expression and alternative splicing (AS). We found that HE impacts expression of genes located within HE regions primarily via cis-acting dosage effect, which led to significant changes in the total expression of homoeolog pairs, especially for homoeologs whose original expression was biased. In parallel, HE influences expression of a large amount of genes residing in non-HE regions by trans-regulation leading to convergent expression of homoeolog pairs. Intriguingly, when taking into account of the original relative homoeolog expression states, homoeolog pairs under trans-effect are more prone to showing convergent response to HE whereas those under cis-effect trended to show subgenome-specific expression. Moreover, HE induced quantitative, largely individual-specific, changes of alternative splicing (AS) events. Like homoeologs expression, homoeo-AS events which related to trans effect were more responsive to HE. HE therefore exerts multifaceted immediate effects on gene expression and, to a less extent, also transcript diversity in nascent allopolyploidy.

Review on Ethnobotany and Phytopharmacology on Mesua ferrea Linn

This work was performed to study the ethnobotany and phytopharmacological properties of M. ferrea L. It is widely distributed in the tropical areas of the world, especially in the Asian countries and is traditionally used by the local peoples for curing diseases ranging from head ache to cancer. Mesua ferrea is cultivated as an ornamental plant and young leaves are reddish yellow in color while mature leaves are blue grey to dark green in appearance with fragrant white flowers. This study reveals that almost all part of the plant have high medicinal property against different ailments. M. ferrea Linn being used for its anticancer, antineoplastic, disinfectant, anti oxidant, hepato-protective, anti arthritic, diuretic, analgesic etc. properties. The phytochemical screening confirms the presence of phenyl coumarins, xanthones, triterpenoids, tannin and saponin as main constituents responsible for its biological activity. It is also used in the cosmetics. This can be used as remedial agents for various health issues. This review reveals the phyto-pharmacological role of this medicinal plant.

Young and Old Leaves Physiological and Metabolite Profiles Analysis on Amino Acids and Organic Acids in Wild Soybean Seedlings Under Nitrogen Deficiency

Background As an important germplasm resource, wild soybean has good tolerance to complex stress environment stress. This study described the differences of physiological and metabolomic changes between common wild soybean (GS1) and the barren tolerance wild soybean (GS2) under low nitrogen (LN) stress. Results The result showed the barren tolerance wild soybean young leaves can maintain relatively stable chlorophyll content and increased the contents of Car;Photosynthetic rate and transpiration rate decreased significantly in in the barren tolerance wild soybean old leaves, but there was no significant change in young leaves; the barren tolerance wild soybean enhanced the enrichment of beneficial ion pairs such as zinc, calcium and phosphorus. The metabolism of amino acids and organic acids in the barren tolerance wild soybean old leaves was vigorous, a large number of beneficial amino acids such as GABA, asparagine and proline were enriched, and the metabolites related to TCA cycle were significantly increased. Conclusion the barren tolerance wild soybean can ensure the nitrogen supply of young leaves by inhibiting the photosynthetic response of old leaves; the relatively stable growth of young leaves also benefits from the effective transport and reuse of beneficial ions from old leaves; More importantly, the enhanced metabolism of specific amino acids and organic acids in GS2 old leaves seemed to play an important role in resisting LN stress. GABA and Asparagine played substantial roles in N storage, C/N balance, antioxidant defense and act as signaling molecule to help GS2 to resist LN stress. Difference organic acids in the old leaves of GS2 increased which could improve the utilization rate of N in the soil. In addition, the strength of fatty acids catabolism and TCA cycle in GS2 old leaves provided energy base for substance transport. The analysis of physiological and metabolite may provide a new perspective for revealing the importance of substance transport and reuse in different plant parts to resist abiotic stress.

Creation of new tomato forms with fungal disease resistance genes based on marker selection

Relevance. The presented studies are aimed at obtaining new forms of tomato with a complex of genes for resistance to fungal diseases in combination with a standard type of bush and dark coloring of fruits based on marker-mediated selection.Methodology. The biological objects of the study are varieties and hybrid forms of tomato from the collection of the Michurinsky SAU. Molecular genetic analysis was performed using the following methods. DNA extraction was carried out from young leaves using a kit for isolation of NC Sample NC manufactured by Agrodiagnostika LLC according to the manufacturer's protocol. Fermentas production kits were used for PCR. Identification of the cladosporosis resistance gene was Cf-19 performed using the DNA marker R7. The presence of a fusarious wilting resistance gene was determined by a I-2/5 marker. The amplification results were visualized by agarose gel electrophoresis.Results. During the research, a collection of varieties and hybrid forms of tomato of the Michurinsky GAU was analyzed in order to identify genes for resistance to cladosporiosis Cf-19 and fusarium wilt I-2. A total of 52 genotypes were analyzed. It was found that most samples (41 samples) are characterized by a heterozygous state of the Cf-19 gene. All indeterminant and semi-determinant forms had both alleles. Of the 23 determinant forms presented in the collection, 10 had only one allele corresponding to recessive homozygote. Among all analyzed tomato genotypes, no dominant homozygous forms were noted. The study of the collection revealed several alleles of the I-2 gene. In total, four fragments corresponding to various alleles were amplified. A total of 50 resistant genotypes have been identified in the collection. Two alleys of the I-2 gene (633/693 bp) were identified in 42 tomato samples. Four varieties are homozygous in one allele (633 bp), which determines resistance. Three varieties have a second resistance allele (566 bp). One genotype has only an allele defining susceptibility (693 bp). On the basis of molecular analysis, as well as an assessment of the type of bush and fetal color, initial forms were selected with subsequent hybridization. 67 hybrid tomato plants were obtained. Evaluation of the presence of resistance genes showed that most of the resulting hybrids are resistant to cladosporiosis and fuzariosis. This is due to the presence of dominant alleles of Cf-19 and I-2 genes in a heterozygous state. Among the resulting hybrids, plants with a bark type of bush were identified. A total of 13 such plants were obtained.Conclusion. Thus, the work carried out allowed to obtain hybrid forms of tomato combine the signs of resistance to two pathogens of fungal diseases and the stem type of the bush. These forms are planned to be used in further selection work.

A Potential Role of Coumestrol in Soybean Leaf Senescence and Its Interaction With Phytohormones

Coumestrol is a natural organic compound synthesized in soy leaves and functions as a phytoalexin. The coumestrol levels in plants are reported to increase upon insect attack. This study investigates the correlation between coumestrol, senescence, and the effect of phytohormones on the coumestrol levels in soybean leaves. Our analysis involving high-performance liquid chromatography and 2-D gel electrophoresis indicated a significant difference in the biochemical composition of soybean leaves at various young and mature growth stages. Eight chemical compounds were specifically detected in young leaves (V1) only, whereas three different coumestans isotrifoliol, coumestrol, and phaseol were detected only in mature, yellow leaves of the R6 and R7 growth stage. MALDI-TOF-MS analysis was used to identify two proteins 3,9 -dihydroxypterocarpan 6A-monooxygenase (CYP93A1) and isoflavone reductase homolog 2 (IFR2) only in mature leaves, which are key components of the coumestrol biosynthetic pathway. This indicates that senescence in soybean is linked to the accumulation of coumestrol. Following the external application of coumestrol, the detached V1-stage young leaves turned yellow and showed an interesting development of roots at the base of the midrib. Additionally, the application of phytohormones, including SA, methyl jasmonate (MeJA), and ethephon alone and in various combinations induced yellowing within 5 days of the application with a concomitant significant increase in endogenous coumestrol accumulation. This was also accompanied by a significant increase in the expression of genes CYP81E28 (Gm08G089500), CYP81E22 (Gm16G149300), GmIFS1, and GmIFS2. These results indicate that various coumestans, especially coumestrol, accumulate during leaf maturity, or senescence in soybean.

Chlorophyllase, a Common Plant Hydrolase Enzyme with a Long History, Is Still a Puzzle

Chlorophyllase (Chlase, CLH) is one of the earliest discovered enzymes present in plants and green algae. It was long considered to be the first enzyme involved in chlorophyll (Chl) degradation, while strong evidence showed that it is not involved in Chl breakdown during leaf senescence. On the other hand, it is possible that CLH is involved in Chl breakdown during fruit ripening. Recently, it was discovered that Arabidopsis CLH1 is located in developing chloroplasts but not in mature chloroplasts, and it plays a role in protecting young leaves from long-term photodamage by catalysing Chl turnover in the photosystem II (PSII) repair cycle. However, there remain other important questions related to CLH. In this article, we briefly reviewed the research progress on CLH and listed the main unanswered questions related to CLH for further study.