Magnetite nanoparticle coating chemistry regulates root uptake pathways and iron chlorosis in plants

Abstract

Understanding the fundamental interaction of nanoparticles at plant interfaces is critical for reaching field-scale applications of nanotechnology-enabled plant agriculture, as the processes between nanoparticles and root interfaces such as root compartments and root exudates remain largely unclear. Here, using iron deficiency–induced plant chlorosis as an indicator phenotype, we evaluated the iron transport capacity of Fe 3 O 4 nanoparticles coated with citrate (CA) or polyacrylic acid (PAA) in the plant rhizosphere. Both nanoparticles can be used as a regulator of plant hormones to promote root elongation, but they regulate iron deficiency in plant in distinctive ways. In acidic root exudates secreted by iron-deficient Arabidopsis thaliana , CA-coated particles released fivefold more soluble iron by binding to acidic exudates mainly through hydrogen bonds and van der Waals forces and thus, prevented iron chlorosis more effectively than PAA-coated particles. We demonstrate through roots of mutants and visualization of pH changes that acidification of root exudates primarily originates from root tips and the synergistic mode of nanoparticle uptake and transformation in different root compartments. The nanoparticles entered the roots mainly through the epidermis but were not affected by lateral roots or root hairs. Our results show that magnetic nanoparticles can be a sustainable source of iron for preventing leaf chlorosis and that nanoparticle surface coating regulates this process in distinctive ways. This information also serves as an urgently needed theoretical basis for guiding the application of nanomaterials in agriculture.

Enhancing iron content and growth of cucumber seedlings with MgFe-LDHs under low-temperature stress

“…Based on these findings, we posit that MgFe-LDHs or other LDHs containing Fe(II) and Fe(III) have the potential to become a new generation of iron fertilizers, serving as a supplement to chelated iron. MgFe-LDHs present unique advantages in iron supplementation strategies compared to other traditional methods: (i) they boast broad applicability, potentially accommodating various soil types; (ii) unlike many other iron-containing nanomaterials, MgFe-LDHs exhibit the ability to selectively adsorb onto plant root hairs, a trait seldom reported for other iron nanomaterials [ 13 ]; and (iii) whereas increased iron content often inhibits growth in certain biological iron supplementation methods [ 2 , 3 ], no such growth inhibition was observed in the present study. Moreover, due to their ease of synthesis and low cost, these materials could be widely used in developing countries.…”

“…Similarly, Yu et al reported that FeO NP fertilization could significantly increase rice ( Oryza sativa L.) yield by regulating the activities of enzymes and enhancing nitrogen fixation, but they did not focus on the accumulation of iron in plants [ 12 ]. Additionally, the use of Fe 3 O 4 nanoparticles coated with citrate (CA) or polyacrylic acid (PAA) to combat Fe deficiency in plants has been explored [ 13 ]. However, these fertilizers cannot replace chelated iron, and the development of green, efficient, and inexpensive new Fe fertilizers is still the key to solving the problem of plant trace element deficiency.…”

Foliar application of iron-based nanofertilizers to wheat grown in a Cd-contaminated field: implications for food safety and biofortification

“…26 Although the significant potential of Fe NMs has been documented under laboratory conditions, studies of foliar application in the field are scarce. 24,27,28…”

Nano iron oxide closes the gap between climate regulation and food security trade-offs

“…Yet, despite the huge potential of this technology, the current investigations of nano-enabled sustainable agriculture mainly focused on commercial crops and short-term studies (i.e., less than one year) [23][24][25] , and almost nothing is known about the long-term in uence of FeONPs on globally distributed crops (e.g., rice) subjected to important GHG emissions and fertilization pressure. Developing the next generation of fertilizers is critical if we are up to continue feeding a growing human population while mitigating climate change.…”