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Titanium dioxide nanoparticles (TiO2 NPs) are among the most commonly used nanomaterials and are most likely to end up in soil. Therefore, it is pertinent to study the interaction of TiO2 NPs with soil microorganisms. The present in vitro broth study evaluates the impacts of low‐dose treatments (0, 1.0, 5.0, 10.0, 20.0, and 40.0 mg L−1) of TiO2 NPs on cell viability, morphology, and plant growth promoting (PGP) traits of rhizobia isolated from mung bean root nodule. Two types of TiO2 NPs, that is, mixture of anatase and rutile, and anatase alone were used in the study. These TiO2 NPs were supplemented in broth along with a multifunctional isolate (Bradyrhizobium sp.) and two reference cultures. The exposure of TiO2 (anatase+rutile) NPs at low concentrations (less than 20.0 mg L−1) enhanced the cell growth, and total soluble protein content, besides improving the phosphate solubilization, Indole‐3‐acetic acid (IAA) production, siderophore, and gibberellic acid production. The TiO2 (anatase) NPs enhanced exopolysaccharide (EPS) production by the test rhizobial cultures. The radical scavenging assay was performed to reveal the mode of action of the nano‐TiO2 particles. The study revealed higher reactive oxygen species (ROS) generation by the TiO2 (anatase) NPs as compared with TiO2 (anatase+rutile) NPs. Exposure to TiO2 NPs also altered the morphology of rhizobial cells. The findings suggest that TiO2 NPs could act as promoters of PGP traits of PGP bacteria when applied at appropriate lower doses. [ABSTRACT FROM AUTHOR]

This manuscript aimed for the generation of γ-irradiation derived mutants of potato genotype PAU/RR-1501 possessing desirable processing traits. Nodal cuttings from virus-free explants were established on basal MS medium and irradiated with different doses (0, 5, 10 and 20 Gy) of γ-irradiation. The 5 and 10 Gy treated plantlets were multiplied and used for micro-tuber induction. Harvested micro-tubers were planted in pots for the selection and evaluation of mutants in M1V2 generation. Four weeks post-treatment, plantlets (5 Gy) showed enhanced growth as compared to the control while 20 Gy treatment exhibited completely ceased shoot growth. The highest number and weight of mini-tubers per plant was recorded for 10 Gy followed by 5 Gy treatment as compared to control. The γ-irradiation treatments caused changes in the skin color and shape of M1V2 tubers. Under the 5 Gy treatment 49.9% of clones produced exhibited cream and 8.53% brown skin color. Nine putative mutants were identified in genotype PAU/RR-1501 exhibiting promising processing traits. [ABSTRACT FROM AUTHOR]

The present study was planned to screen the sweet sorghum genotypes at the sensitive seedling stage against salinity with specific morpho-physiological and biochemical attributes that could contribute to their adaptability to salinity stress. Therefore, 14 sweet sorghum genotypes were subjected to five different NaCl salt concentrations (0 mM (C), 50 mM, 100 mM, 150 mM and 200 mM), and 5 days after germination (DAG), the seedlings were evaluated for morpho-physiological parameters (percent germination, shoot and root lengths, seedling biomass and seedling vigor indexes I and II), total sugars, total chlorophyll and Na+/K+ ratio. Correlation, heat map and principle component analysis revealed that germination percentage is highly correlated with seedling vigor indexes (I and II) and seedling fresh weight. The sweet sorghum genotypes showed a significant reduction in morpho-physiological traits with a minimum effect seen in PHULE VASUNDHARA and SSV 84 with increasing salt stress. Two clusters were obtained on the basis of all studied traits: in cluster I, PHULE VASUNDHARA and SSV 84 with better seedling growth, biochemical parameters (total sugars and total chlorophyll) and higher K+ concentration were grouped together and in cluster II, 12 genotypes were clustered together. Further, gene expression analysis of ion transporters (HKT-6 and HAK) confirmed the observed lower Na+/K+ ratio due to more HKT-6 ion transporter gene expression in the roots of the selected tolerant PHULE VASUNDHARA as compared to the selected sensitive SPV 2074 with more expression of ion transporter HAK, suggesting that this Na+/K+ ratio could be a reliable trait for salinity tolerance screening at seedling growth stage. Further, tolerant genotypes could be a prominent resource for further use in salinity tolerance breeding of sweet sorghum. [ABSTRACT FROM AUTHOR]

During shoot apex development, the plants undergo a very complex transition phase of flowering for successful reproduction, seed/cone setting and fruit development. The conversion of vegetative shoot meristems to floral meristems depends upon numerous endogenous, exogenous factors and flowering genes for the development of floral parts. The perennial crops suffer from the limitation of the innate ability to keep some meristems in the vegetative state for the polycarpic growth habit leading to the long juvenile phase. Conventional breeding approaches viz. selection of early flowering parental lines, flower thinning and grafting are time-consuming requiring more time for the release of a new cultivar which is undesirable for rapid crop improvement. The best way to accelerate the perennial plant breeding improvement programs and to reduce the long juvenile phase is the induction of early flowering through the utilization of biotechnological approaches. The ability to allow the transmission of an early flowering gene to the progeny in a Mendelian fashion is the major advantage of biotechnological interventions. The introgression of early flowering traits from non-commercial germplasm or sexually compatible species to perennial species through the biotechnological aspects will act as a boon for crop improvement in future studies. The present review gives an overview of various flowering genes in perennial crops accompanying the implementation of biotechnological approaches including overexpression studies, RNA interference, Virus-induced flowering and CRISPR-Cas approaches that will help in reducing the period for induction of flowering in perennial crops. [ABSTRACT FROM AUTHOR]