Impact of nitrogen and phosphorus fertilizers on Cry1Ac protein contents in transgenic cotton.

M A Zia,S Shoukat,S H Shah,A Shahzad,Z Hussain,S U Khan,S Ali

doi:10.1590/1519-6984.246436

Abstract

Application of different fertilizers to check the efficiency of expression of Bt (Bacillus thuringiensis) gene in one of the leading commercialized crops (cotton) against Lepidopteran species is of great concern. The expression of Cry protein level can be controlled by the improvement of nutrients levels. Therefore, the myth of response of Cry toxin to different combinations of NP fertilizers was explored in three Bt cotton cultivars. Combinations include three levels of nitrogen and three levels of phosphorus fertilizers. Immunostrips and Cry gene(s) specific primer based PCR (Polymerase Chain Reaction) analysis were used for the presence of Bt gene that unveiled the presence of Cry1Ac gene only. Further, the ELISA (enzyme-linked immunosorbent assay) kit was used to quantify the expression of Cry1Ac protein. Under various NP fertilizers rates, the level of toxin protein exhibited highly significant differences. The highest toxin level mean was found to be 2.3740 and 2.1732 µg/g under the treatment of N150P75 kg ha-1 combination while the lowest toxin level mean was found to be 0.9158 and 0.7641 µg/g at the N50P25 kg ha-1 level at 80 and 120 DAS (Days After Sowing), respectively. It was concluded from the research that the usage of NP fertilizers has a positive relation with the expression of Cry1Ac toxin in Bt cotton. We recommend using the N150P50 kg ha-1 level as the most economical and practicable fertilizer instead of the standard dose N100P50 kg ha-1 to get the desired level of Cry1Ac level for long lasting plant resistance (<1.5). The revised dose of fertilizer may help farmers to avoid the cross-resistance development in contradiction of insect pests.

Highlights

Cotton (Gossypium hirsutum L.) is one of the foremost export cash crops and is considered as the backbone of Pakistan’s economy (Tayyib et al, 2005)
The seed of Bt cotton varieties namely FH-113, Bt121 and MNH-886 were acquired from National Institute for Genomics & Advanced Biotechnology (NIGAB), National Agricultural Research Centre (NARC), Islamabad
The results provide the evidence of Cry1Ac insecticidal gene only in local cotton cultivars

Summary

Introduction

Cotton (Gossypium hirsutum L.) is one of the foremost export cash crops and is considered as the backbone of Pakistan’s economy (Tayyib et al, 2005). About 15% of the arable land in Pakistan is covered by this crop. Increased yield of this crop is very much important for developing country like Pakistan to boost up its economy. About 8% of the total GDP and 54% of export is covered by cotton in Pakistan (Rehman, 2020). The Bt transgenic cotton is environment and human friendly as it reduces the use of toxic pesticides. It is not useful against all the cotton pests but it has resistance against few insect species (Mehmood et al, 2012)

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Results

Discussion

Conclusion