Bt Jute Expressing Fused δ-Endotoxin Cry1Ab/Ac for Resistance to Lepidopteran Pests.

Shuvobrata Majumder,Subrata Satpathy,Chirabrata Sarkar,Prosanta Saha,Karabi Datta,Bheemanna S Gotyal,Swapan K Datta

doi:10.3389/fpls.2017.02188

Abstract

Jute (Corchorus sp.) is naturally occurring, biodegradable, lignocellulosic-long, silky, golden shiny fiber producing plant that has great demands globally. Paper and textile industries are interested in jute because of the easy availability, non-toxicity and high yield of cellulosic biomass produced per acre in cultivation. Jute is the major and most industrially used bast fiber-producing crop in the world and it needs protection from insect pest infestation that decreases its yield and quality. Single locus integration of the synthetically fused cry1Ab/Ac gene of Bacillus thuringiensis (Bt) in Corchorus capsularis (JRC 321) by Agrobacterium tumefaciens-mediated shoot tip transformation provided 5 potent Bt jute lines BT1, BT2, BT4, BT7 and BT8. These lines consistently expressed the Cry1Ab/Ac endotoxin ranging from 0.16 to 0.35 ng/mg of leaf, in the following generations (analyzed upto T4). The effect of Cry1Ab/Ac endotoxin was studied against 3 major Lepidopteran pests of jute- semilooper (Anomis sabulifera Guenee), hairy caterpillar (Spilarctia obliqua Walker) and indigo caterpillar (Spodoptera exigua Hubner) by detached leaf and whole plant insect bioassay on greenhouse-grown transgenic plants. Results confirm that larvae feeding on transgenic plants had lower food consumption, body size, body weight and dry weight of excreta compared to non-transgenic controls. Insect mortality range among transgenic feeders was 66–100% for semilooper and hairy caterpillar and 87.50% for indigo caterpillar. Apart from insect resistance, the transgenic plants were at par with control plants in terms of agronomic parameters and fiber quality. Hence, these Bt jutes in the field would survive Lepidopteran pest infestation, minimize harmful pesticide usage and yield good quality fiber.

Highlights

Jute is the highest bast fiber-producing crop in the world
Shoot tips were isolated from 5 day-old seedlings (Figure 1B), followed by infiltration with Agrobacterium LBA4404 strain, harboring a pCAMBIA1301-actin-cry1Ab/Ac-nos construct (Figure 1A), as per previously standardized jute shoot tip transformation method with some modifications (Saha et al, 2014a)
The cry1Ab/Ac Gene Integration Confirmed by polymerase chain reaction (PCR), Southern Hybridization, Reverse Transcriptase (RT)-PCR and Quantitative Real-Time PCR (qRT-PCR) Analysis

Summary

Introduction

Jute is the highest bast fiber-producing crop in the world. It is the second most important fiber crop after cotton. Jute fibers are naturally occurring, biodegradable, available and non-toxic. Among more than 170 species, only Corchorus capsularis (white jute) and C. olitorius (tossa jute) are cultivated in the major fiber producing countries. Jute fiber and its products have global demand. Development of Bt Jute in Australia, Germany, Japan, Russia, Spain, United Kingdom, and United States, because of the environment-friendly nature of the fibers. For the year 2013–2014, 99.82% of the total global jute production was from the developing countries of Asia, where India contributed 56.85% (1944 thousand tones), Bangladesh 40.67% (1391 thousand tones), China 1.03% (35.5 thousand tones), Uzbekistan 0.61% (21 thousand tones) and Nepal 0.45% (15.5 thousand tones) (FAO, 2017)

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