IOSR Journal of Biotechnology and Biochemistry (IOSR-JBB) ISSN: 2455-264X, Volume 7, Issue 4 (Jul. – Aug. 2021), PP 11-24 www.iosrjournals.org DOI: 10.9790/264X-0704021124 www.iosrjournals.org 11 | Page Microbial Effector Proteins: Green Inducer for Systemic Acquired Resistance in Plants Ros Azrinawati Hana Bakar 1 ; Norliza Abu Bakar 2,* ; Khairulmazmi Ahmad 1,5* ; Noor Azmi Shaharuddin 6 ; Mohd As’wad Abdul Wahab 1 ; Osamanu Haruna Ahmed 3,4 1 (Department of Plant Protection, Faculty of Agriculture, Universiti Putra Malaysia, Serdang, 43400, Malaysia) 2(Biotechnology and Nanotechnology Research Centre, Malaysia Agriculture Research and Development Institute (MARDI), Serdang, 43400 Malaysia) 3(Department of Crop Science, Faculty of Agricultural Science and Forestry Bintulu Campus Sarawak, Universiti Putra Malaysia, Bintulu 97008, Malaysia) 4(Institute of Tropical Agriculture and Food Security, Universiti Putra Malaysia, Serdang, 43400, Malaysia) 5(Institute Plantation Studies (IKP), Universiti Putra Malaysia, 43400, Selangor, Malaysia) 6(Department of Biochemistry, Faculty of Biotechnology and Molecular Science, Universiti Putra Malaysia, 43400 Serdang, Selangor, Malaysia) Abstract: Systemic acquired resistance (SAR) is considered as a “whole-plant” barrier response that has been been expressed by the plant following the localized exposure to phytopathogens. This defense mechanism is controlled by a line pathway of either interaction of one or more signaling compounds such as salicylic acid (SA) and jasmonic acid (JA) with the help of regulatory protein known NPR1. Upon challenged by phytopathogen and in response to other environmental stimulants, the host plant responds by developing an increased SAR that navigates itself to remote tissues and determines a regulated resistance in distal, the healthy tissues to encourage defense against pathogen to besiege. For decades, the phenomenon of SAR via plant resistance inducers application in the laboratory has been described by several researchers. However, the progress towards understanding SAR and the application of SAR in open fields remain limited. Therefore, this review discusses the significant knowledge of SAR mechanisms and its application in the field as parts of plant disease control strategies. Key Word: Systemic Acquired Resistance; Microbial effector protein; Virulence factor; Field application; Plant defense mechanism. -------------------------------------------------------------------------------------------------------------------------------------------- Date of Submission: 28-07-2021 Date of Acceptance: 12-08-2021 -------------------------------------------------------------------------------------------------------------------------------------------- I. Introduction The Agricultural sustainability is the ultimate aim of any agricultural production systems. This should enable current and the future generations to satisfy their needs in addition to enhancing environmental quality and natural resources. According to the United Nations Food and Agriculture Organization (FAO), a minimum 50% increase in agricultural food production by that time is required to meet the demand in a scenario of moderate economic growth. Considering the limited availability of arable land, the key emphasis is to increase the return per area and lower yield losses to cope with this in-creasing food demand 1,2 . Therefore, the efficiency of plant disease management contribution to the global food production is essential 3 . Currently, plant disease control includes predominantly preventive steps, mostly covering cultural activities such as disease-resistant cultivars and crop rotation 4,5 . Contradictory to organic pesticides, chemical pesticides or industrial pesticides are utilized for both pre-emptive and curing disease approaches 5,6,7 . In current agriculture practices, chemical usage for plants crucially improves the crop yield and quality, food safety and optimizing shelf- life 8 . In spite of the positive contributions of pesticides in controlling plant diseases and pests, concerns have raised about the adverse effects of chemical pesticides on human health and their environmental impact including soil pollution, water pollutions, and toxicity to beneficial organisms 9,10.11,12 . As depicted by neonicotinoid-resistant insects and fungi being unresponsive towards broad-spectrum strobilurin or azole fungicides, it significantly demonstrates pests’ insusceptible development and disease to the all -out usage of chemical pesticides 13,14,15 .