Differentiation of the High Night Temperature Response in Leaf Segments of Rice Cultivars with Contrasting Tolerance

High night temperatures (HNT) affect rice yield in the field and induce chlorosis symptoms in leaves in controlled chamber experiments. However, little is known about molecular changes in leaf segments under these conditions. Transcript and metabolite profiling were performed for leaf segments of six rice cultivars with different HNT sensitivity. The metabolite profile of the sheath revealed a lower metabolite abundance compared to segments of the leaf blade. Furthermore, pre-adaptation to stress under control conditions was detected in the sheath, whereas this segment was only slightly affected by HNT. No unique significant transcriptomic changes were observed in the leaf base, including the basal growth zone at HNT conditions. Instead, selected metabolites showed correlations with HNT sensitivity in the base. The middle part and the tip were most highly affected by HNT in sensitive cultivars on the transcriptomic level with higher expression of jasmonic acid signaling related genes, genes encoding enzymes involved in flavonoid metabolism and a gene encoding galactinol synthase. In addition, gene expression of expansins known to improve stress tolerance increased in tolerant and sensitive cultivars. The investigation of the different leaf segments indicated highly segment specific responses to HNT. Molecular key players for HNT sensitivity were identified.

Heracleum piliferum (Apiaceae), a new species from central Nepal

A new species, Heracleum piliferum (Apiaceae), is described from the Annapurna mountain massif, central Nepal. The new species is related to H. forrestii and H. hemsleyanum and differs from them in dense pubescence of petioles, short triangular sheaths of stem leaves, 2-pinnate leaf blades, shallow notched terminal leaf segments, crenulate leaf margin, larger terminal umbels, and broadly winged lateral ribs of the mericarps.

Micropropagation of Pelargonium odoratissimum (L.) L’Her. through petioles and leaves

Pelargonium odoratissimum (L.) L’Her is a hard rooting plant and the common methods of propagation via stem cuttings are not successful with this species. therefore, tissue culture methods have been experienced for the mass-propagation of this high-valued species. Intact leaves, leaf segments and petiole sections derived from nodal explants in vitro were employed for the optimization of P. odoratissimum micropropagation. The treatment combinations used were MS and 1/2 MS media supplemented with 6-benzylaminopurine, BAP (1, 1.5, 2 and 4.5 mg.L-1) and 1-naphthaleneacetic acid, NAA (0.1, 1 and 1.5 mg.L-1). With leaf segments, the lowest browning incidence, the greatest callogenesis and the highest number of shoots were obtained with the media containing 1.5 mg.L-1 BAP and 1 mg.L-1 NAA. Two mg.L-1 BAP + 0.1 mg.L-1 NAA kept the same results for petiole explants. Intact leaves showed the best results for the three mentioned treatments with 1 mg.L-1 BAP + 1 mg.L-1 NAA. 0.2 mg.L-1 NAA caused the highest rooting percentage and the greatest mean data for the number and length of the roots. Rooted plantlets were transferred to the pots containing 1:1 peat-moss and perlite. Acclimatization of the plantlets was followed by 90 % of survival rate in the greenhouse. The protocol employed would be a potent one to present for the extension section.

Geranium aedonianum a new species of Geraniaceae from Ladakh, India

Geranium aedonianum sp. nov. collected from Panikhar village of Kargil district, Ladakh, India belonging to subg. Geranium, is described and illustrated. It differs from other closely allied species: Geranium collinum, G. himalayense and G. strictipes by the obtrullate-obtriangular leaf segments that are narrower at base and with fewer lobes, longer pedicels, staminal filament whitish having broad base tapering smoothly towards apex and glandular hairs along the margins on upper part and its longer fruits.

An Efficient And Quick Protocol For In Vitro Multiplication Of Snake Plant, Sansevieria Trifasciata Var. Laurentii [Prain]

An efficient protocol was developed for quick propagation of snake plant under in vitro conditions. Leaf segments were surface sterilized and inoculated on Murashige and Skoog media supplemented with 3% sucrose, 0.8% agar, and various concentrations of indole-3-butyric acid. Cultures were maintained for 4-5 weeks at standard conditions to allow root induction and elongation. Shoot induction is triggered upon altering the culture room temperature to 37±2⁰C. Multiple shoots were witnessed at higher IBA concentrations. Another 5 weeks later, individual plantlets were excised and hardened for 2 weeks in soil preparation contained in small cups before transferring to big sized pots.

Shoot Regeneration Is Not a Single Cell Event

Shoot regeneration is a key tool of modern plant biotechnology. While many researchers use this process empirically, very little is known about the early molecular genetic factors and signaling events that lead to shoot regeneration. Using tobacco as a model system, we found that the inductive events required for shoot regeneration occur in the first 4–5 days following incubation on regeneration medium. Leaf segments placed on regeneration medium did not produce shoots if removed from the medium before four days indicating this time frame is crucial for the induction of shoot regeneration. Leaf segments placed on regeneration medium for longer than five days maintain the capacity to produce shoots when removed from the regeneration medium. Analysis of gene expression during the early days of incubation on regeneration medium revealed many changes occurring with no single expression pattern evident among major gene families previously implicated in developmental processes. For example, expression of Knotted gene family members increased during the induction period, whereas transcription factors from the Wuschel gene family were unaltered during shoot induction. Expression levels of genes involved in cell cycle regulation increased steadily on regeneration medium while expression of NAC genes varied. No obvious possible candidate genes or developmental processes could be identified as a target for the early events (first few days) in the induction of shoot regeneration. On the other hand, observations during the early stages of regeneration pointed out that regeneration does not occur from a single cell but a group of cells. We observed that while cell division starts just as leaf segments are placed on regeneration medium, only a group of cells could become shoot primordia. Still, these primordia are not identifiable during the first days.

Regeneration of Genetically Stable Plants from in Vitro Vitrified Leaves of Different Carnation Cultivars

This study was conducted to investigate the efficacy of shoot regeneration from different leaf types (normal leaves and vitrified leaves) from three different carnation cultivars ‘Kumbuyl’, ‘Denev’, and ‘Jinju’ using different combinations of 3-indole butyric acid (IBA) and thidiazuron (TDZ) concentrations. The shoot tips cultured on Murashige and Skoog (MS) basal media (Type 1 media) produced normal leaves, while those cultured-on media supplemented with plant growth regulators and/or vitamin (Type 2 media and Type 3 media) produced vitrified leaves for all cultivars. Culture of normal leaf segments on MS medium containing different combinations of IBA and TDZ concentrations induced callus in all treatments; however, the callus was unable to induce shoots and finally became necrotic. In contrast, no callus induction was observed in the control (hormone-free treatment). When vitrified leaf segments underwent the same treatments, shoots were induced from the vitrified leaves (derived from Type 2 media) but were unhealthy and gradually died, whereas those induced from Type 3 media were vitrified and healthy. The optimal combination for the best shoot regeneration and number of shoots per explants varied depending on the genotypes used. The vitrified shoots induced from the leaves of Type 3 media transformed into normal shoots and survived well under greenhouse conditions. According to the results of random amplified polymorphic DNA (RAPD) analysis, the banding patterns of twelve primers that were detected in vitrified leaf-induced normalized shoots were identical to those of normal in vitro grown plants, indicating that no genetic variation had occurred during the procedure. Taken together, this study indicates that vitrified leaves can be used for shoot regeneration of recalcitrant carnation cultivars, regardless of the genotypes and types of vitrified leaves. However, as the number of shoots per explants was still low, further investigation is warranted to obtain a more efficient shoot regeneration protocol for genetic transformation of the cultivars.

Parasites as niche modifiers for the microbiome: A field test with multiple parasites

Parasites can affect and be affected by the host’s microbiome, with consequences for host susceptibility, parasite transmission, and host and parasite fitness. Yet, there are two aspects of the relationship between parasite infection and the host microbiome that remain little understood: the nature of the relationship under field conditions, and how the relationship varies among parasite species. To overcome these limitations, we assayed the within-leaf fungal community in a grass population to investigate how diversity and composition of the fungal microbiome are associated with natural infection by fungal parasites with different feeding strategies. We hypothesized that parasites that more strongly modify niches available within a host will thereby alter the microbial taxa that can colonize the community and be associated with greater changes in microbiome diversity and composition. A parasite that creates necrotic tissue to extract resources (necrotrophs) may act as a particularly strong niche modifier whereas one that does not (biotrophs) may not. Barcoded amplicon sequencing of the fungal ITS region revealed that the microbiome of leaf segments that were symptomatic of necrotrophs had lower fungal diversity and distinct composition compared to segments that were asymptomatic or symptomatic of other parasites. There were no clear differences in fungal diversity or composition between leaf segments that were asymptomatic and segments that were symptomatic of other parasite feeding strategies. This supports the hypothesis that within-host niches link infection by parasites to the host’s microbiome. Together, these results highlight the importance of parasite traits in determining parasite impacts on the host’s microbiome.

Morphological characteristics of the leaf blade and the variety of dill morphotypes

Relevance. Common dill (Anethum graveolens L.) is an annual plant of the celery family (Apiaceae). It has alternated variously repeatedly pinnatisected simple leaves character- ized by a number of morphological features including color, presence of waxy bloom, size and density of the final segments, size and shape of the leaf blade. Leaves on different nodes of the same plant can be variable. Environment conditions of plant cultivation also affect some morphological characteristics of the leaf (inc. size of the leaf and its final segments). But, under the same conditions each variety of dill possess a certain set of morphological features that determine the variety identity. In recent years, dill varieties with new morphological features of the leaf blade have emerged, and it is important to evaluate and classify the existing morphologic diversity of the plant.Methods. Several methods are currently used to describe morphological features of dill leaves structure: developed by VIR (All-Russian Institute of Plant Genetic Resources), UPOV, the plant approbation manual, description of leafy vegetables in “Cultivated Flora” compendium. There are similarities and differences between the methods in description of characteristics and their grouping according to the extent of the characters. In this study the current methods for description of the morphological features of dill leafs were compared. The described morphological evaluation of the dill varieties was carried out at 2016–2018 in open field in the Research Institute of Vegetable Crop Breeding (LLC), in the “Gavrish-Slobodskoy” Plant Breeding Center (Pavlovskaya Sloboda, Istrinsky district, Moscow region).Results. As a result, it was revealed that the UPOV method more comprehensively describes the morphological characteristics of dill leaf blade. This method can be extended in the following direction: Establish groups according to the length of leaf, using leaf blade length without petiole: small leaf blade – 5-12 cm, medium – 12-25 cm, large – 25- 40 cm; Establish new character: a density of leaf segments (in parts of the 2nd order) and identify the following groups: thin (up to 5 segments), medium density (6-15 segments), and dense (16 or more segments) arrangement of the segments; Establish new character: segment length, grouping it according their actual length: up to 1 cm – short, from 1 to 1.5 cm – medium, and more than 1.5 cm – long leaf segments. According to the evaluated leaf morphological characteristics: size, color, presence of waxy bloom, “leaf patterns”, the dill plants are very diverse. Two dill morphotypes can be distinguished by presence or absence of waxy bloom, 3 morphotypes by the leaf shape (diamond-shaped, elongated, triangular), and 27 morphotypes – by location and size of the final leaf segments.