Gopalakrishnan Subramaniam Sathya Arumugam Vijayabharathi Rajendran Editors Plant Growth Promoting Actinobacteria A New Avenue for Enhancing the Productivity and Soil Fertility of Grain Legumes Plant Growth Promoting Actinobacteria ThiS is a FM Blank Page Gopalakrishnan Subramaniam • Sathya Arumugam • Vijayabharathi Rajendran Editors Plant Growth Promoting Actinobacteria A New Avenue for Enhancing the Productivity and Soil Fertility of Grain Legumes Editors Gopalakrishnan Subramaniam Sathya Arumugam Bio-Control, Grain Legumes Bio-Control, Grain Legumes ICRISAT, Patancheru, Hyderabad ICRISAT, Patancheru, Hyderabad Telangana, India Telangana, India Vijayabharathi Rajendran Bio-Control, Grain Legumes ICRISAT, Patancheru, Hyderabad Telangana, India ISBN 978-981-10-0705-7 ISBN 978-981-10-0707-1 (eBook) DOI 10.1007/978-981-10-0707-1 Library of Congress Control Number: 2016939389 # Springer Science+Business Media Singapore 2016 This work is subject to copyright. All rights are reserved by the Publisher, whether the whole or part of the material is concerned, specifically the rights of translation, reprinting, reuse of illustrations, recitation, broadcasting, reproduction on microfilms or in any other physical way, and transmission or information storage and retrieval, electronic adaptation, computer software, or by similar or dissimilar methodology now known or hereafter developed. The use of general descriptive names, registered names, trademarks, service marks, etc. in this publication does not imply, even in the absence of a specific statement, that such names are exempt from the relevant protective laws and regulations and therefore free for general use. The publisher, the authors and the editors are safe to assume that the advice and information in this book are believed to be true and accurate at the date of publication. Neither the publisher nor the authors or the editors give a warranty, express or implied, with respect to the material contained herein or for any errors or omissions that may have been made. Printed on acid-free paper This Springer imprint is published by Springer Nature The registered company is Springer Science+Business Media Singapore Pte Ltd. We dedicate this book to Dr Om Prakash Rupela (1948–2015), Ex Principal Scientist (Microbiology), ICRISAT Patancheru, Telangana, India, who mentored and encouraged us to work toward biological options for agriculture. ThiS is a FM Blank Page Foreword The year 2016 is a special one for pulses. The United Nations announced 2016 as the “International Year of Pulses (2016 IYOP)” in order to empha- size the need to focus on pulses as critical components for global food and nutritional security and to create awareness and understanding of the challenges faced in pulse farming and value chains. Pulses, or grain legume crops, are often referred to as “poor man’s meat,” as they offer a cost- effective alternative to animal proteins. Besides protein, their richness in micronutrients and other vital elements make pulses critical entities in food and feed value chains around the world. As with all crops, pulse production is hindered by biotic and abiotic constraints, including pest and pathogen attacks, infertile soils, and climate variability and change. Improved cultivars and management practices are continuing and required outputs from research to ensure that crops are productive and profitable and their grains provide nutritious and healthy food. Production practices must also address the risks associated with the use of pesticides and fertilizers and must explore alternate options, especially biological resources, for enhancing the production of pulses. In the context of biological options, plant growth-promoting (PGP) bacte- ria, actinobacteria in particular, are well known for their usefulness in crop production and protection and in maintaining soil health. Actinobacteria are commonly found in soil, compost, fresh and marine water, and decomposing organic materials, and they produce secondary metabolites of agricultural importance. Such metabolites hold fungicidal, bactericidal, insecticidal, and plant growth-promoting traits and can fill the need for biological agents. Exploration of such potential PGP actinobacteria offers the prospect of alternative chemical crop protection agents and so improved environmental health and sustainability. I commend the editors, Gopalakrishnan Subramaniam, Sathya Arumugam, and Vijayabharathi Rajendran of the book Plant Growth- Promoting Actinobacteria: A New Avenue for Enhancing the Productivity and Soil Fertility of Grain Legumes. They have the expertise in basic research, crop production, and plant protection with reference to the use of PGP actinomycetes from the laboratory to field levels. This book contains 19 chapters reporting on the combination of grain legumes with actinomycetes, with details starting from the diversity of actinomycetes vii viii Foreword through the commercialization of PGP actinomycetes and their metabolites. Each chapter is stand alone and contributes to the field. This book is a strong contribution to supporting pulses in food and feed systems globally. It critically assesses the data and offers study on practical aspects of field applications. I strongly endorse this book as it makes a lasting contribution to the field of plant growth-promoting actinomycetes and for its contribution to sustainable agriculture around the globe. Deputy Director General - Research Peter Carberry International Crops Research Institute for the Semi-Arid Tropics, Patancheru, Hyderabad, India January 21, 2016 Preface Grain legumes are the abundantly used plant protein source mainly in developing countries of South East Asia, Africa, and Latin America. They are a cost-effective option for animal proteins including fish, meat, and dairy products and hence attained the name “poor man’s meat.” Besides the protein, their richness in micronutrients and other vital elements made them essential entities in food and feed. Their unique association with rhizobia contributes 65 % of nitrogen necessity in agriculture through the process of symbiotic nitrogen fixation. Their better adaption as intercrop with cereals or tuber crops helps in income generation and livelihood resilience. Cultivation of grain legumes benefits small holder families since they are the primary cultivators of these crops, especially the women since their partici- pation in value chain paves a way for combating nutritional deficiencies and improving the well-being of their children. Constraints related to the production of legumes are pest and pathogen attacks, unstable yield, poor adaptation, and climate changes. Besides this, the increasing per capita consumption of grain legumes by low-income and developing countries made a gap between grain legume supply and demand. In case of chickpea, groundnut, and pigeonpea, the current shortfall of 7 million tons of supply in low-income food-deficit countries is projected to increase by almost 50 % by 2020, if the same production system continues. The productivity of grain legumes is stagnant for the last two to three decades in spite of using the best breeding and molecular techniques. Further, the increasing costs associated with the improved cultivars and negative effects associated with pesticides and fertilizer use necessitate alternate options. The United Nations also emphasized the need for focusing on grain legumes by announcing year 2016 as the International Year of Pulses (2016 IYOP), in order to create awareness and understanding of the challenges faced by pulse farmers. Rhizospheric soil, inhabited and influenced by the plant roots, is usually rich in nutrients when compared to the bulk soil, due to the accumulation of numerous amino acids, fatty acids, nucleotides, organic acids, phenols, plant growth regulators/promoters, putrescine, sterols, sugars, and vitamins released from the roots by exudation, secretion, and deposition. This results in enrichment of microorganisms (10–100-folds than the bulk soil) such as bacteria, fungus, algae, and protozoa, among which bacteria influence plant ix x Preface growth in a most significant manner. Such rhizobacteria present in various proximity to the roots as (1) bacteria living in soil near the roots (rhizo- sphere), (2) bacteria colonizing the root surface (rhizoplane), (3) bacteria residing in root tissue (endophytes), inhabiting spaces between cortical cells, and (4) bacteria living inside cells in specialized root structures, or nodules, which include two groups – the legume-associated rhizobia and the woody plant-associated Frankia sp. Such microbes which promote plant growth are referred as plant growth-promoting (PGP) bacteria. This includes the genera Bacillus, Pseudomonas, Erwinia, Caulobacter, Serratia, Arthrobacter, Micrococcus, Flavobacterium, Chromobacterium, Agrobacterium, Hyphomicrobium, Rhizobium, Bradyrhizobium, Sinorhizobium, Azorhizobium, Mesorhizobium Allorhizobium, and Strepto- myces. Besides rhizospheric organisms, microbes present in vermicompost, vermiwash, and earthworm, in specific earthworm gut, nephridia, and ali- mentary canal, contribute to the beneficial properties of vermicompost and vermiwash in enhancing soil health, plant growth, and hence agricultural productivity. Reports for the diversity of bacteria, fungi, and actinomycetes in vermicompost and earthworm and also for the enhanced plant growth by vermicompost application are available. Actinomycetes, a group of Gram- positive bacteria, are found commonly in soil, compost, fresh, and marine water, and