Search

Sea purslane (Sesuvium portulacastrum) was cultivated for two 90-day sequences at two spacings, and with various soil amendments, to evaluate its potential to arrest the increase in soil salinity and sodicity associated with irrigation using paper- and pulp-mill effluent. Its phytodesalination capacity (PDC) with respect to Na ranged from 162 to 226 kg/ha in the first sequence and 167 to 250 kg/ha in the second sequence; the PDC is reliable even under drought stress. Addition of amendments, in particular pressmud compost, increased the average Na+ uptake by 38%, leading to the highest PDC of 250 kg/ha for a single crop sequence. [ABSTRACT FROM AUTHOR]

Rice is one of the most cultivated cereal crops worldwide and its productivity is affected by several biotic and abiotic factors. The gram-negative bacterium, Xanthomonas oryzae pv. oryzae (Xoo) severely impacts rice productivity by causing bacterial leaf blight disease. During infection, Xoo secretes a TALe protein which binds to effector binding element (EBE) present in the promoter sequence of susceptible genes, such as SWEET genes in order to make the plants vulnerable to infection. Mutations in EBE were shown to prevent binding of TALe and in turn result in enhanced resistance to the pathogen. In an attempt to engineer resistance in ASD16 to Xoo strains that secrete PthXo1, the EBE of promoter of SWEET11 gene was edited through CRISPR/Cas9 tool. Genome editing of ASD16, through Agrobacterium-mediated transformation resulted in seventeen transgenic events. Thirty one plants belonging to thirteen independent transgenic events turned out to be mutants possessing biallelic or homozygous mutations. Bioassay studies on twelve T0 mutant plants against Xoo revealed that eleven mutant plants were found to be resistant/ moderately resistant to the Xoo strain, indicating the potential of CRISPR technology in creating allelic variations which could be exploited in disease resistance breeding programmes. [ABSTRACT FROM AUTHOR]

Bacterial leaf blight (BLB) of rice is considered to be a disease of economic importance as the disease causes severe yield losses in all rice growing regions. Transcription activator like effector (TALE) molecules are produced by the pathogen, Xanthomonas oryzae pv. oryzae (Xoo) bind to the effector binding element (EBE) of the promoter of SWEET gene and activates transcription of SWEET genes, making the plant susceptible to the disease. Innate resistance to Xoo in certain rice genotypes is due to mutations in EBE present in the upstream regulatory region of SWEET genes. CRISPR--mediated targeted modification of susceptibility gene/promoter is an effective approach to develop BLB resistance in rice. The present study was an attempt to repress TALE triggered signalling via introducing indels in the EBE of OsSWEET13 gene in a local popular rice genotype, CO51 employing CRISPR/Cas9 mediated genome editing tool with a view to imparting BLB resistance. Agrobacterium-mediated transformation using immature embryos followed by regeneration resulted in four independent transformation events. Five plants representing three events were found to have one nucleotide deletion in the target sequence. These deletion mutations in EBE could potentially interfere with the binding of the corresponding TALE to confer resistance against certain strains of BLB. [ABSTRACT FROM AUTHOR]

Adenine base editor (ABE) creates A to G transitions within its editing window. In the present study, an ABE was used to target a stretch of six amino acid residues, VLFPNL in translation initiation factor four gamma (eIF4G) gene of rice. Agrobacterium-mediated transformation of rice cultivar ASD16 resulted in T0 events with high mutation efficiency of 89.29 %. Substitution mutations of A > G occurred within the editing window of four to eight bases at A7 > G7 (74.67 %) and A4 > G4 (2.46 %). Non-canonical substitutions of G > C/A was also observed at G15 > C15 (9.29 %) and G8 > A8 (1.15 %). A total of 15 missense base substitution events affecting the target residue was identified. Taken together, the present study showed that ABEs create unexpected base substitutions besides efficient canonical editing of A > G in the rice genome. [ABSTRACT FROM AUTHOR]

Toxicity of nine indigenous Bacillus thuringiensis (Bt) isolates collected from Tamil Nadu, India were tested against fall armyworm, Spodoptera frugiperda. At 30 µg/ml concentration, two Bt isolates viz., T350 and T532 recorded 100 per cent mortality whereas isolates T527 and T532 registered 96 per cent mortality against neonate larvae of S. frugiperda in leaf dip bioassay. SDS PAGE analysis of spore crystal mixture revealed the presence of Cry1 and Cry2 proteins with visible bands at 130 kDa and 65 kDa. PCR screening results showed the presence of cry1 (cry1A, cry1Aa, cry1Ab), cry2 (cry2Aa, cry2Ab) in four isolates and vip3A genes in three isolates but cry9 gene was not present in any of the isolates tested. [ABSTRACT FROM AUTHOR]