Som Dutt

Translation initiation in plants: roles and implications beyond protein synthesis

Protein synthesis is a ubiquitous and essential process in all organisms, including plants. It is primarily regulated at translation initiation stage which is mediated through a number of translation initiation factors (eIFs). It is now becoming more apparent that in addition to synthesis of proteins, eIFs also regulate various aspects of plant development and their interaction with environment. Translation initiation factors, such as eIF3, eIF4A, eIF4E, eIF4G, and eIF5A affect different processes during vegetative and reproductive growth like embryogenesis, xylogenesis, flowering, sporogenesis, pollen germination, etc. On the contrary, eIF1A, eIF2, eIF4, and eIF5A are associated with interaction of plants with different abiotic stresses, such as high temperature, salinity, oxidative stress, etc. Similarly, eIF4E and eIF4G have roles in interaction with many viruses. Therefore, the translation initiation factors are important candidates for improving plant performance and adaptation. A large number of genes encoding eIFs can functionally be validated and utilized through genetic engineering approaches for better adaptability and performance of plants by inhibiting/minimizing or increasing expression of desired eIF(s).

Key players associated with tuberization in potato: potential candidates for genetic engineering

Abstract Tuberization in potato (Solanum tuberosum L.) is a complex biological phenomenon which is affected by several environmental cues, genetic factors and plant nutrition. Understanding the regulation of tuber induction is essential to devise strategies to improve tuber yield and quality. It is well established that short-day photoperiods promote tuberization, whereas long days and high-temperatures inhibit or delay tuberization. Worldwide research on this complex biological process has yielded information on the important bio-molecules (proteins, RNAs, plant growth regulators) associated with the tuberization process in potato. Key proteins involved in the regulation of tuberization include StSP6A, POTH1, StBEL5, StPHYB, StCONSTANS, Sucrose transporter StSUT4, StSP5G, etc. Biomolecules that become transported from “source to sink” have also been suggested to be important signaling candidates regulating the tuberization process in potatos. Four molecules, namely StSP6A protein, StBEL5 RNA, miR172 and GAs, have been found to be the main candidates acting as mobile signals for tuberization. These biomolecules can be manipulated (overexpressed/inhibited) for improving the tuberization in commercial varieties/cultivars of potato. In this review, information about the genes/proteins and their mechanism of action associated with the tuberization process is discussed.

Potential of Indian potatoes for the management of hyperglycemia

Potatoes are less favoured by health conscious people due to the notion that it has high glycaemic index. Anti-hyperglycemic and antioxidative potential of Indian potato cultivars were evaluated with the aim to remove the misconception. Glycaemic index was measured indirectly through estimating resistant starch, amylose content and activity of α-amylase and α-glucosidase inhibitors from cooked tubers of 46 Indian potato cultivars. The α-glucosidase inhibitory activity ranged from 0 to 52.8% and was observed only in 14 cultivars, viz., Kufri Anand, Kufri Arun, Kufri Khasigaro, Kufri Kuber, Kufri Kundan, Kufri Muthu, Kufri Naveen, Kufri Neela, Kufri Pushkar, Kufri Red, Kufri Sadabahar, Kufri Safed, Kufri Sutlej and Kufri Swarna. α-amylase inhibitory activity was found only in cultivar Kufri Frysona (20.5%). Resistant starch content ranged from 1.22 to 1.93 mg/100 mg DW with highest value in Kufri Garima (1.93 mg/100 mg DW). Amylose content ranged from 10.8 to 27.6 mg/100 mg DW and was the maximum in processing cultivar Kufri Chipsona-3 (27.6 mg/100 mg DW). The highest activities of α-glucosidase inhibitors along with considerable resistant starch content was observed in cultivars, viz. Kufri Kuber, Kufri Khasigaro, Kufri Muthu, Kufri Naveen and Kufri Pushkar. Therefore, these potato cultivars can be used as speciality potatoes as these attributes have potential to prevent hyperglycemia helping manage the incidence of type II diabetes.

Antimicrobial Activity of Potato Starch-Based Active Biodegradable Nanocomposite Films

Food-borne pathogens such as Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus) create a lot of problems worldwide and are a major concern of food producers and consumers. To protect the food from spoilage due to these bacteria, antimicrobial packaging is one of the most promising active packaging systems. Environmental concerns associated with plastic waste emphasized the development of packaging films from natural polymers such as starch. Therefore, in the present study, potato starch-based biodegradable and antimicrobial nanocomposite films were prepared with constant concentration of zinc oxide nanoparticles using casting method. Films were prepared using three antimicrobial agents, cinnamon oil, clove oil, and potassium sorbate and were tested against four microbes, S. aureus, E. coli, Salmonella typhi (S. typhi), and Campylobacter jejuni (C. jejuni). The films prepared with clove oil were most effective against S. aureus (22–100% inhibition), those prepared with cinnamon oil were effective against C. jejuni (19–22% inhibition) and growth of E. coli was inhibited (33–40% inhibition) to maximum extent by potassium sorbate incorporated films. However, for complete inhibition of C. jejuni and E. coli, higher concentrations of cinnamon oil and potassium sorbate are required. Increasing concentration of antimicrobial agents decreased the tensile strength of the films. Tensile strength decreased up to 13% in cinnamon oil films, 23% in clove oil films and up to 34% in potassium sorbate incorporated films. Based on the results, it can be concluded that cinnamon oil is a better antimicrobial agent due to its least effect on tensile strength and also due to its antibacterial effect against the three bacteria.