Transgenic cotton applied to phytonematode control using in plant RNA interfering strategy.

Cotton (Gossypium hirsutum) is one of the most important commodities worldwide, and it is among the ten largest sources of wealth in the Brazilian agribusiness. However, its productivity is constantly threatened by biotic and abiotic factors. Plant-parasitic nematodes (PPN) are one of the most damaging pathogens, representing global losses of approximately US$ 100 bi/annual. More and more, biotechnology tools have contributed to overcoming these constraints through the development of tolerant or resistant plants. Interfering RNA (RNAi) technology has been successfully exploited in different plant species for achieving resistance against different pathogens. The cross-talk of these engineered RNAi produced in planthas been shown to be an efficient strategy to knockdown essential genes in PPN. Previous studies of our research team have identified several potential molecules from nematodes involved in nematode-plant interaction. The Mi-1, Mi-2 and Mi-3 genes are, respectively, an avirulence protein, a cysteine protease involved in plant parasitism, and a protein involved in the formation of egg mass matrix. Here, cotton GM plants constitutively overexpressing a hairpin-derived dsRNA targeting simultaneously these three genes of Meloidogyne incognita were obtained from biolistic-transformation. Transgenic plants were in vitro and ex vitro (leaf-painting) selected using herbicide Imazapyr and QuickStix kit for LibertyLink® (bar gene).Twelve PCR-positive events were characterized and plants from T1 and T2 generation were challenged with M. incognita, using root gall index and number of eggs to evaluate plant resistance/susceptibility. Data will be significant to the nematode management in cotton crops

Identification and characterization of the GmRD26 soybean promoter in response to abiotic stresses: potential tool for biotechnological application.

Made available in DSpace on 2019-11-26T18:11:07Z (GMT). No. of bitstreams: 1 document.pdf: 2063634 bytes, checksum: a340a2af742819c4e99df6eedffbadce (MD5) Previous issue date: 2019bitstream/item/205521/1/document.pd

Stability and tissue-specific Cry10Aa overexpression improves cotton resistance to the cotton boll weevil.

The cotton boll weevil (CBW, Anthonomus grandis) is the most destructive cotton insect pest affecting cotton crops. To overcome this problem, CBW-resistant genetically modified cotton plants overexpressing Bacillus thuringiensis entomotoxins were successfully obtained. Previous results showed that the overexpression of Cry10Aa protoxin led to high mortality of the CBW larvae in greenhouse conditions. In this study, we advanced three more generations (T2 to T4), with several cotton events constitutively overexpressing the Cry10Aa protoxin, and the transgene stability and agronomic performance were investigated. In addition, stable transgenic cotton overexpressing the Cry10Aa active (Cry10Aa protoxin lacking the -helix N-terminal) driven by cotton flower bud-specific promoters were generated and characterized. Cotton events constitutively or tissue-specifically overexpressing the Cry10Aa protein (protoxin or active) represented mortality percentages of the CBW larva of up to 85 % in plants under greenhouse conditions. Events overexpressing the Cry10Aa active under control of the flower bud-specific promoter showed higher protein accumulation in stamens and carpels compared to the events with constitutive expression. Our findings suggested that the high stability of the Cry10Aa transgene and the elevated expression level and protein accumulation in flower bud tissues (primarily in stamen and carpels) contribute to improved resistance to CBW larvae. Finally, some notable events were selected with potential for future field trials in different cotton- producing regions of Brazil. Therefore, cotton events overexpressing high levels of the Cry10Aa protein in flower bud tissue may have a strong potential for commercial use in the integrated management of CBW