Endophytic bacteria and rare earth elements; promising candidates for nutrient use efficiency in plants

Review: Endophytic microbes and their potential applications in crop management

“…In one experiment it was found that grass plants obtained approximately 30% of nitrogen from rhizophagy . Gene responses of plants infected with endophytes often show that plant antioxidants and nitrate transporters are among genes upregulated in plants . These upregulated genes may be the result of increased oxidative reactions in roots and increased liberation of nitrates resulting from protein degradation.…”

“…Add to this, the general and prevalent assumption that most microbes on plants are pathogenic or have negligible effects has contributed to lack of efforts to understand the roles of endophytes in plant growth promotion and plant health improvement. Over the past few decades the gradual development of a body of research that demonstrated that endophytes are common in plants and positively affect plant development and health represents an important advancement in understanding the importance and functionality of endophytes . Recently, the exploration for useful endophytes and other microbes for agricultural applications has been enhanced by emergence of companies that have as their primary focus development and marketing of plant biostimulants (including endophytes) .…”

“…3,4 Other endophytes may be recruited from the soil but similarly benefit plants. 4 Endophytic microbes are important components of plants, and they function in the following ways: (i) increase nutrients acquired by plants, [5][6][7][8] (ii) defend plants from pathogens and insects, [9][10][11] (iii) increase stress tolerance in plants, 12,13 (iv) modulate plant development, [13][14][15] and (v) suppress weed growth. 16 The particular mechanisms by which endophytic microbes fill the various functions in plants likely differ depending on the microbe and plant.…”

“…[24][25][26] Gene responses of plants infected with endophytes often show that plant antioxidants and nitrate transporters are among genes upregulated in plants. 7,8,13 These upregulated genes may be the result of increased oxidative reactions in roots and increased liberation of nitrates resulting from protein degradation. Another experiment involving tomato seedlings employed elevated carbon dioxide to suppress superoxide formation and extraction of nutrients from microbes; here rhizophagy cycle suppression resulted in reduced absorption into seedlings of potassium, calcium and sulfur (J.…”

“…Over the past few decades the gradual development of a body of research that demonstrated that endophytes are common in plants and positively affect plant development and health represents an important advancement in understanding the importance and functionality of endophytes. 1,7,8,35,45,46,58 Recently, the exploration for useful endophytes and other microbes for agricultural applications has been enhanced by emergence of companies that have as their primary focus development and marketing of plant biostimulants (including endophytes). 59 To facilitate development of applications for microbes in agriculture, the recent U.S. government 2018 Agriculture Improvement Act (also known as the 2018 Farm Bill) in the United States and regulatory documents in the European Union explicitly addressed biostimulants and their regulation.…”