Acta Physiologiae Plantarum

Safari, Fateme; Akramian, Morteza; Salehi-Arjmand, Hossein

doi: 10.1007/s11738-020-3018-3pmid: N/A

Worldwide, salt stress is one the major limiting factors of crop production particularly in arid and semi-arid areas. Here, responses of salt-stressed lemon balm (Melissa officinalis L.) to exogenously applied protective substances including reduced glutathione (GSH), proline and salicylic acid were studied to elucidate the regulatory roles of these protectants at the physiochemical and molecular levels. Under salinity, supplying exogenous protectants improved the contents of photosynthetic pigments and proline, triggered accumulation of phenolic compounds and expression of related biosynthetic genes, enhanced antioxidant capacity and modulated stress-induced lipid peroxidation which indicate the regulatory functions of applied protectants in lemon balm plant in this condition. In addition, there were strong correlations between the expression levels of phenylalanine ammonia-lyase (PAL) and chalcone synthase (CHS) genes, as key components of the phenylpropanoid pathway and the contents of total phenolics and flavonoids. In this study, a partial-length of lemon balm CHS gene was also cloned and sequenced for the first time.

Singh, Veerpartap; Jawandha, S. K.; Gill, P. P. S.

doi: 10.1007/s11738-020-3014-7pmid: N/A

To enhance the storage potential of pear cv. Punjab Beauty fruit, the effect of putrescine (PUT) treatments was evaluated by analysing various physico-chemical characteristics and enzymatic activities. Postharvest dip treatments of PUT (1, 2 and 3 mM) were given to uniform and healthy fruit, while tap water was used for the control fruit. Treated fruit were stored at 0–1 °C and 90–95% RH for 75 days. Evaluation of fruit quality parameters was made on the 0th, 15th, 30th, 45th, 60th, 67th and 75th days of storage. The PUT treatments (2 and 3 mM) proved to be effective to diminish the softening and enhance the storage potential with acceptable quality. These treatments also suppressed the pectin methyl esterase and cellulase activity, reduced the weight loss and spoilage compared with control. Moreover, 2 and 3 mM PUT applications delayed colour changes, retained higher soluble solids content, starch content and titratable acidity at the end of storage than in control. These findings suggested that exogenous PUT application of 2 and 3 mM could effectively maintain fruit quality and prolong the storage potential of pear cv. Punjab Beauty fruit by reducing the softening during storage.

Singh, Devendra; Geat, Neelam; Rajawat, Mahendra Vikram Singh; Prasanna, Radha; Saxena, Anil Kumar

doi: 10.1007/s11738-019-2997-4pmid: N/A

One of the important limiting factors to realising the benefits of modern high- yielding crop varieties is the availability of iron (Fe) in the soil, which often leads to Fe deficiency in food grains. The main objective of this study was to evaluate the role of two siderophore-producing endophytes (Arthrobacter sulfonivorans DS-68 and Enterococcus hirae DS-163) in the biofortification of grains with Fe and enhance yield in four genotypes of wheat (Triticum aestivum L.) in soils with low and high available Fe content. Endophyte inoculation increased the surface area, volume, length of roots and number of root tips by 78.27, 75, 71 and 44%, respectively, relative to the uninoculated control (recommended dose of fertilizers; RDF), across genotypes and soil types. In the low available-Fe soil, inoculation with endophytes increased grain yield twofold relative to the control (RDF), whereas in the high available-Fe soil, the increase was only 1.2-fold across genotypes. In general, endophyte inoculation caused an increase of 1.5-fold and 2.2-fold in iron concentration in grains over the RDF + FeSO4 treatment and uninoculated control (RDF), respectively, across all the genotypes and both soil types. Such siderophore-producing endophytes can be recommended as bioinoculants to mitigate iron deficiencies in the soil and enhance crop productivity.

Zhou, Xianrong; Khare, Tushar; Kumar, Vinay

doi: 10.1007/s11738-020-3013-8pmid: N/A

Plant micro-RNAs (miRNAs) are a distinct class of non-coding, small regulatory RNA molecules emerging as key regulators of growth, development, and stress responses in plants. Therefore, plant miRNAs are looked upon as one of the most potent tools for crop improvement including generation of stress resilient crops. These small elements regulate the gene expression patterns at post-transcriptional as well as translational stages, and are proved to be concomitant with epigenetic regulations in plants during growth and developmental phases, and stress-mediated modulations/adaptations. Recent advancements in sequencing technologies have delivered the high-resolution clusters of sequence information from various organisms, making the miRNA characterization procedure more reliable, rapid, and promising. A typical miRNA investigation usually incorporates preparation of wide-range small RNA library and high-throughput sequencing, followed by the computational analysis of the obtained sequences using a variety of in silico tools. These in silico tools are proving vital in context of identification of miRNAs, their corresponding targets, and inclusive reports on metabolic networks incorporating the identified miRNAs. Current in silico progressions have made available a wide range of tools and databases for miRNA analysis. Therefore, diverse approaches can be seen amongst the researchers which might vary in terms of specificity of analysis, such as plant-, function-, target-specific analysis of miRNAs. Through this review, we discuss the recent developments and current understandings about the plant miRNAs and present the workflow of plant miRNAs including modern high-precision approaches for isolation, identification, target prediction and confirmation, miRNA-target network analysis, and functional characterization of plant miRNAs.

Brar, Harmanjeet Singh; Thakur, Anirudh; Singh, Harpreet; Kaur, Nirmaljit

doi: 10.1007/s11738-019-2998-3pmid: N/A

Use of protective coverings can be an economically viable option in fruit nurseries than in fully mature commercial orchards. In protected nurseries, photoselective coverings can influence the growth of rootstocks, budding success, and budding growth of the budded scion cultivar. The effect of photoselective coverings (white, silver, green, red and stainless steel net house) along with open conditions (control) was studied on plant growth, nutrient uptake and root growth of rough lemon and Carrizo citrange rootstock seedlings which were subsequently budded with Kinnow and Daisy mandarin cultivar buds, respectively. The rough lemon plants under red net had better height, internodal length and budding success, while in open conditions, higher seedling diameter, root diameter, shoot and root dry weight, leaf number and secondary root number were recorded in rough lemon seedlings. The Carrizo seedlings in red net had better seedling diameter, internodal length, leaf area and number, shoot dry weight and budding success. The higher nitrogen, phosphorus, potassium and zinc levels were recorded in the leaves of rough lemon and Carrizo citrange under red shade net. The plant height of rough lemon seedlings was positively correlated to internodal length, budding success and leaf areaas well as leaf phosphorus and iron levels. The highest buddable seedlings were recorded in open conditions but, budding success in red shade net house. The highest sprout lengths of Kinnow and Daisy mandarin saplings were recorded in red net followed by green net and white net. Higher photosynthesis and stomatal conductance were recorded under red shade net, whereas lowest PAR interception was recorded in open conditions.

Karwa, Sourabh; Bahuguna, Rajeev Nayan; Chaturvedi, Ashish K.; Maurya, Sadhana; Arya, Sunder Singh; Chinnusamy, Viswanathan; Pal, Madan

doi: 10.1007/s11738-020-3016-5pmid: N/A

Rice crop is known to be sensitive to heat stress particularly at the flowering stage. Breeding approaches for improving heat tolerance in rice needs understanding of heat tolerance mechanisms and suitable heat tolerance donors. A study was planned for screening of rice genotypes and identification of novel heat tolerant donor(s) and physiologically characterize the component traits using contrasting set of genotypes in green house environment. Genotypes were categorized as tolerant and sensitive to heat stress using heat susceptibility index and cumulative stress response index for spikelet fertility, pollen viability, and grain yield. Among the set of genotypes screened, IET 22218 recorded high spikelet fertility (> 85%), pollen viability (> 95%) at high temperature (39–44 °C) with relative humidity (> 60–80%). This genotype recorded higher photosynthesis, canopy temperature depression, and accumulation of endogenous level of polyamines both under optimum and heat stress environments. Moreover, IET 22218 genotype recorded lower H2O2 accumulation, membrane damage and higher activity of antioxidant enzymes. Heat stress tolerance in IET 22218 was at par with heat tolerant checks, i.e., Nagina22 (N22) and Nerica L-44 (NL-44). Interestingly, IET 22218 also maintained lower chalkiness (< 34%) and higher head rice yield (> 85%) under heat stress. Based on above traits IET 22218 was selected as the novel donor for heat tolerance. The study concludes that induced polyamines and antioxidant enzymes activity in IET 22218 under stress were associated with lowering oxidative stress and maintained higher pollen viability and spikelet fertility under heat stress environment. However, more studies are recommended to understand the role of polyamines in heat stress tolerance specifically in rice.

Manoharlal, Raman; Saiprasad, G. V. S.

doi: 10.1007/s11738-020-3015-6pmid: N/A

The concept of plant growth regulators (PGRs) in modulating the plant physiological processes through epigenetic modification(s) is emerging. The present work aims to elucidate the histone (de)acetylation-associated epigenetic changes in ethylene (ET)-primed sprouts of soybean [Glycine max (L.) Merrill]. Our results demonstrated that ethephon (donor source of ET) priming (ETp) in soybean significantly enhanced the: (1) germination rate, (2) global histone H3 (H3ac) and H3 lysine 9 (H3K9ac) acetylation levels, (3) histone acetyltransferases activity (concomitant with reduced histone deacetylases activity), (4) cellular acetyl-CoA pool and (5) global de novo RNA synthesis. As a gene-specific case study, ETp resulted in relative reduced starch content, concomitant with an enhanced mRNA accumulation, transcriptional rate and proximal promoter H3K9ac levels of α-amylase 1 (GmαAMY1). Taken together, the proposed epigenetic role of ET as a ‘histone-code’ modulator in soybean sprouts could provide a novel insight on PGR-induced epigenetic re-programming and signifies a broader scope for future epigenetic studies in other agronomical important crops.

Morgante, Carolina Vianna; Nunes, Sávio Luiz Pereira; Chaves, Agnaldo Rodrigues de Melo; Ferreira, Cláudia Fortes; Aidar, Saulo de Tarso; Vitor, Alison Borges; de Oliveira, Eder Jorge

doi: 10.1007/s11738-019-3005-8pmid: N/A

Cassava (Manihot esculenta) is a staple food crop mostly grown in the tropics. Successful cultivation in marginal areas derives from its ability to withstand difficult environmental conditions. Aiming at providing new insights into drought tolerance in Manihot spp., we performed physiological and molecular analyses of early drought response in three cassava varieties and in the wild species, Manihot glaziovii (maniçoba). Plants grown in pots were subjected to three water regimes for 5 days, based on soil field capacity (FC): 75% (well-watered plants); 45% (moderately stressed plants), and 20% (severely stressed plants), under greenhouse condition. Analysis of leaf gas exchange showed a downward trend in photosynthesis, stomatal conductance, and transpiration, with intensification of the stress, in all genotypes, being significantly reduced only at 20% FC. Maniçoba stood out for maintaining a positive carbon balance in severe stress condition via stomatal aperture control. Photoinhibition of the photosystem II by drought was also evident only at 20% FC. There was no clear association between proline accumulation and drought stress tolerance. Expression analysis of nine genes encoding heat-shock proteins, transcription factors, a cell redox homeostasis protein, and a no-hit protein confirmed the activation of classical stress-responsive pathways, especially those involved in oxidative damage avoidance. These results reinforce the intrinsic drought tolerance of cassava, highlight the superior performance of maniçoba under water deficit conditions, and give insights into drought phenotyping in cassava and contribute to further development of functional molecular markers to be used in assisted breeding.

Mahajan, Mitali; Pal, Probir Kumar

doi: 10.1007/s11738-019-2996-5pmid: N/A

Rosa damascena is an important essential oil-bearing industrial crop. Rose essential oil is extremely precious natural ingredient in aromatic, cosmetic, food, and pharmaceutical industries. However, ecology and plant nutrition play major roles in flower yield and composition of oil. The main objective was to understand the effects of seasonal variation and foliar application of Ca(NO3)2 on R. damascena under the western Himalayan conditions. Thus, a field experiment was conducted with 12 treatment combinations involving two cropping seasons (2012–2013 and 2013–2014) and six levels of Ca(NO3)2 (water spray as control, Ca(NO3)2 at 2.5, 5.0, 7.5, 10.0 and 12.5 g L−1 of water). The first cropping season produced significantly higher flower yield (1044.55 g bush−1) than the second cropping season (699.89 g bush−1). Irrespective of the cropping seasons, the foliar application of Ca(NO3)2 at 10.0 g L−1 registered significantly higher flower yield (993.56 g bush−1) compared with the controlled treatment, but remained statistically at par with 7.5 and 12.5 g L−1. Although the essential oil content in flower was not affected by both the factors, the variations were observed in chemical compositions of essential oil. Analysed data revealed that the effect of seasonal variation on compositions of essential oil was more pronounced compared to the application of Ca(NO3)2. The PCA biplots also indicated the highly positive correlations among the major hydrocarbons. Despite the significant effects of seasonal variation on the accumulations of total N and P in leaves, insignificant results were found for K and Chl. The results suggest that flower yield and compositions of oil are governed by the environmental conditions; moreover, the higher flower yield can be obtained through the foliar application of Ca(NO3)2 under rainfed conditions.

Guo, Chunyan; Zhang, Nan; Liu, Cunqi; Xue, Jingjing; Chu, Jianzhou; Yao, Xiaoqin

doi: 10.1007/s11738-019-2992-9pmid: N/A

Drying treatments are an effective method for preserving original beneficial ingredients of postharvest plants. This work supplied the suitable drying conditions of three drying methods by investigating the changes of lotus leaves’ quality and antioxidant activity. The results indicated that: (1) Oven drying (55–65 °C) was the most appropriate way to keep the higher contents of alkaloids and amino acids, and the higher activities in DPPH radical scavenging and hydroxyl radical scavenging in lotus leaf treated with three drying methods; (2) Steam kill-enzyme torrefaction (3–5 min) was the most appropriate method for keeping the higher contents of flavone and the higher activities of superoxide radical scavenging in lotus leaf treated with three drying methods; (3) Microwave drying (680–850 W) was the most appropriate means to keep the higher contents of vitamin C, soluble sugar and protein in lotus leaf treated with three drying methods; (4) The color of lotus leaf treated with microwave treatments was more bright green than that treated with the other two methods; Therefore, the actual conditions of each drying means have to be taken into consideration when use the drying means.