Rajnish Khanna

• Doctor of Philosophy
• i-Cultiver

In 1723, Anthonie van Leeuwenhoek, the “master of fleas and father of microbiology”, died at the age of 90 [...]

In 1872, the 6th (last) edition of Charles Darwin’s Origin of Species was published, wherein he had added a well-known section on Mivart’s criticism of 1871 concerning natural selection. Here, we describe Darwin’s ideas on “lower vs. higher organisms”, inclusive of his hypothesis of steady “perfection” and species co-existence during the evolutiona...

The rejection of some US-science books by the Texas Board of Education because of their presentation of climate change and evolution, as discussed in The Wall Street Journal (Nov. 17, 2023), is very disturbing and reminiscent to the struggle for science education in India, on which we want to comment. We document that “parochial nationalism” may be...

The above-ground (phyllosphere) plant microbiome is increasingly recognized as an important component of plant health. We hypothesized that phyllosphere bacterial recruitment may be disrupted in a greenhouse setting, and that adding a bacterial amendment would therefore benefit the health and growth of host plants. Using a newly developed synthetic...

A plant's growth and development are shaped by its genome and the capacity to negotiate its environment for access to light, water, and nutrients. There is a vital need to understand the interactions between the plant, its physical environment, and the fertilizers used in agriculture. In this study, a commercially available volcanic ash fertilizer,...

In a recent Review Article on Gregor Mendel’s (1822–1884) work with pea (Pisum sativum)-plants, it was proposed that this crop species should be re-vitalized as a model organism for the study of cell- and organ growth. Here, we describe the effect of exogenous gibberellic acid (GA3) on the growth of the second internode in 4-day-old light-grown pea...

A plant's growth and development are shaped by its genome and the capacity to negotiate its environment for access to light, water, and nutrients. There is a vital need to understand the interactions between the plant, its physical environment, and the fertilizers used in agriculture. In this study, a commercially available volcanic ash fertilizer,...

The above-ground plant microbiome (the phyllosphere) is increasingly recognized as an important component of plant health. We hypothesized that phyllosphere interactions may be disrupted in a greenhouse setting, where microbial dispersal is limited, and that adding a microbial amendment might yield important benefits to the host plant. Using a newl...

Food crops are grown with fertilizers containing nitrogen, phosphorus, and potassium (macronutrients) along with magnesium, calcium, boron, and zinc (micronutrients) at different ratios during their cultivation. Soil and plant-associated microbes have been implicated to promote plant growth, stress tolerance, and productivity. However, the high deg...

Food crops are grown with fertilizers containing nitrogen, phosphorus, and potassium (macronutrients), along with magnesium, calcium, boron, and zinc (micronutrients) at different ratios during their cultivation. Soil and plant associated microbes have been implicated to promote plant growth, stress tolerance, and productivity. However, the high de...

In their Research Article ”Molecular insights into the complex mechanics of plant epidermal cell walls” (Science 372, 706–711; 2021), Y. Zhang et al. analyzed, based on a new physical model, the functions of cellulose nanofibrils and matrix polysaccharides during elongation growth. Their results indicate that stiff, ca. 3 nm wide cellulose fibrils,...

One century ago (Jan. 9, 1921), the Russian biologist Constantin S. Merezhkowsky, who proposed the endosymbiotic origin of plastids, committed suicide at the age of 66 years. Here, we provide Merezhkowsky’s original observations on chloroplast development in seedlings and recount the career and achievements of the “founding father” of this Anti-Dar...

One century ago, the German chemist and botanist Wilhelm Pfeffer (1845–1920) died, shortly after finishing his last lecture at the University of Leipzig. Pfeffer was, together with Julius Sachs (1832–1897), the founder of modern plant physiology. In contrast to Sachs, Pfeffer’s work was exclusively based on the principles of physics and chemistry,...

A pioneer in the study of the effect of light on plant development, Wilhelm Pfeffer (1845–1920), outlined both modes of plant development in darkness and in light– today known as skoto- and photo- morphogenesis, respectively. By exploring the current understanding of these pathways in Arabidopsis, we speculate on the possible mechanisms of cell and...

Abstract In 1821, the Swiss botanist A. P. de Candolle (1788–1841) introduced the term ‘‘Arabidopsis’’ to denote a group of dicotyledonous plants (family Brassicaceae). Here, we recount the history of Arabidopsis research from 1588 to 2020, with a focus on light and plant development. We document that plant stem cell research, with commercial appl...

The year 2020 marks the 150th anniversary of the elucidation of the process of plant organ growth at the cellular level by Julius Sachs (1870). In this Addendum to a Review Article in Molecular Plant, we describe this fundamental discovery and argue that the etiolated grass coleoptile still represents the system of choice for the experimental analy...

Despite growing interest in utilizing microbial-based methods for improving crop growth, much work still remains in elucidating how beneficial plant-microbe associations are established, and what role soil amendments play in shaping these interactions. Here, we describe a set of experiments that test the effect of a commercially available soil amen...

A fermented liquid product composed of a broad spectrum of microbes, fermentation by-products and organic acids, VESTA (SOBEC Corporation, Fowler CA), is a highly commercially successful biological product. VESTA has been sold for over 20 years and applied successfully on more than 80 different commercial crops grown on large fields located in diff...

In 1963, a monograph by Thomas D. Luckey entitled Germfree Life and Gnotobiology was published, with a focus on animals treated with microbes and reference to the work of Louis Pasteur (1822–1895). Here, we review the history and current status of plant gnotobiology, which can be traced back to the experiments of Jean-Baptiste Boussingault (1801–18...

Reorganization of the cortical microtubule cytoskeleton is critical for guard cell function. Here, we investigate how environmental and hormonal signals cause these rearrangements and find that COP1, a RING-finger-type ubiquitin E3 ligase, is required for degradation of tubulin, likely by the 26S proteasome. This degradation is required for stomata...

Crop yield is a highly complex quantitative trait. Historically, successful breeding for improved grain yield has led to crop plants with improved source capacity, altered plant architecture, and increased resistance to abiotic and biotic stresses. To date, transgenic approaches towards improving crop grain yield have primarily focused on protectin...

Gene expression data for overexpression and miRNA targets described in this manuscript. (XLSX)

The single B-box clade in Arabidopsis thailana and Glycine max. The Arabidopsis thaliana genome contains seven single B-box domain genes while the paleopolyploid Glycine max genome contains thirteen single B-box genes. Phylogenetic analysis indicates that GmBBX52 and GmBBX53 are orthologs of the Arabidopsis thaliana BBX32 gene. (TIFF)

Overexpression of GmBBX52 (line 7) or GmBBX53 (line 2) in soybean affects the transcript abundance of central clock components near ZT 0. Levels of both central clock components GmLCL2 (A) and GmTOC1 (B) were assayed by quantigene RNA extraction and expression analysis from V2 leaf tissue harvested from soybean plants grown in a controlled environm...

Commercial varieties used in this study. (XLSX)

Changes observed in clock gene expression in the microarray experiment. (XLSX)

Phylogenetic analysis of the entire A. thaliana and G. max B-box gene family. (TIFF)

Primers used to quantitate transgene expression in this study. (XLSX)

BBX ID and the public gene IDs of the Arabidopsis and Soy Bbox genes described within the manuscript. (XLSX)

A B-box zinc finger protein, B-BOX32 (BBX32), was identified as playing a role in determining hypocotyl length during a large-scale functional genomics study in Arabidopsis (Arabidopsis thaliana). Further analysis revealed that seedlings overexpressing BBX32 display elongated hypocotyls in red, far-red, and blue light, along with reduced cotyledon...

The E3 ubiquitin ligase COP1 (CONSTITUTIVE PHOTOMORPHOGENIC1) plays a key role in the repression of the plant photomorphogenic development in darkness. In the presence of light, COP1 is inactivated by a mechanism which is not completely understood. This leads to accumulation of COP1’s target transcription factors, which initiates photomorphogenesis...

The Arabidopsis thaliana genome encodes >1500 transcription factors, and ∼45% of these belong to families specific to plants ([Riechmann et al., 2000][1]). Comparison of the entire complement of transcription factors of Arabidopsis , Drosophila melanogaster , Caenorhabditis elegans , and

PHYTOCHROME-INTERACTING FACTOR5 (PIF5), a basic helix-loop-helix transcription factor, interacts specifically with the photoactivated form of phytochrome B (phyB). Here, we report that dark-grown Arabidopsis thaliana seedlings overexpressing PIF5 (PIF5-OX) exhibit exaggerated apical hooks and short hypocotyls, reminiscent of the triple response ind...

The phytochrome (phy) family of sensory photoreceptors (phyA-phyE in Arabidopsis thaliana) induces changes in target-gene expression upon light-induced translocation to the nucleus, where certain members interact with selected members of the constitutively nuclear basic helix-loop-helix transcription factor family, such as PHYTOCHROME-INTERACTING F...

In previous time-resolved microarray-based expression profiling, we identified 32 genes encoding putative transcription factors, signaling components, and unknown proteins that are rapidly and robustly induced by phytochrome (phy)-mediated light signals. Postulating that they are the most likely to be direct targets of phy signaling and to function...

The PsPK3 gene of the garden pea encodes a presumptive protein-serine/threonine kinase whose catalytic domain is closely related to the second messenger-dependent kinases. To demonstrate that PsPK3 is a functional protein kinase, its catalytic domain was expressed in and purified from Escherichia coli for in vitro activity assays. The recombinant c...

Evidence has been presented that a negative transcriptional feedback loop formed by the genes CIRCADIAN CLOCK ASSOCIATED (CCA1), LATE ELONGATED HYPOCOTYL (LHY) and TIMING OF CAB (TOC1) constitutes the core of the central oscillator of the circadian clock in Arabidopsis. Here we show that these genes are expressed at constant, basal levels in dark-g...

A single-crystal silicon micromachined air turbine supported on gas-lubricated bearings has been operated in a controlled and sustained manner at rotational speeds greater than 1 million revolutions per minute, with mechanical power levels approaching 5 W. The device is formed from a fusion bonded stack of five silicon wafers individually patterned...

The phytochrome (phy) family of sensory photoreceptors (phyA to phyE) in Arabidopsis thaliana control plant developmental transitions in response to informational light signals throughout the life cycle. The photoactivated conformer of the photoreceptor Pfr has been shown to translocate into the nucleus where it induces changes in gene expression b...

Different Arabidopsis phytochrome (phy) family members (phyA through phyE) display differential photosensory and/or physiological functions in regulating growth and developmental responses to light signals. To identify the genes regulated by phyB in response to continuous monochromatic red light (Rc) during the induction of seedling de-etiolation,...

To define the functions of genes previously identified by expression profiling as being rapidly light induced under phytochrome (phy) control, we are investigating the seedling de-etiolation phenotypes of mutants carrying T-DNA insertional disruptions at these loci. Mutants at one such locus displayed reduced responsiveness to continuous red, but n...

This paper reports solutions to the problem of profile control of narrow trenches in the vicinity of wider topographic features, as well as for etching high aspect ratio, anisotropic trenches with depths in the 300 to 500 um range, and of widths between 12 to 18 um.

A single-crystal silicon air turbine supported on gas lubricated bearings has been operated in a controlled and sustained manner at rotational speeds greater then I nullion rpm and power levels approaching 5 W. The device is a second-generation version of the microbearing rig first reported by Lin et al. [I], and is the first raicromachine to opera...

The PsPK3 and PsPK5 genes of the garden pea encode protein-serine/threonine kinases whose catalytic domains are closely related to known signal transducing kinases from animals and fungi. The PsPK3 polypeptide is predicted to be located in the nucleus, whereas PsPK5 is a homologue of NPH1, the probable blue light receptor for phototropism from Arab...

To understand the role protein kinases play in photoregulated seedling development, a set of protein kinases and their genes from the garden pea were studied. The genes encoding these kinases, PsPK1 through PsPK5 , are differentially expressed during de-etiolation of seedlings. I focused on PsPK3 and PsPK5 because transfer of etiolated seedlings to...