**4. Conclusion**

from this review are whether other single-gene manipulations methods can also produce such effects as *PIMT.* Other research concerns might be the investigation of the effects of enhanced expression of seed vigor genes/proteins on other seed traits like nutrient value, potential health

Since 2013, newer *-omics* tools that allow genome-editing and gene targeting are poised to contain ethical concerns of GMOs because of its capacity for precise modulation of traits of interest with unprecedented control and efficiency. A set of techniques called clustered, regularly interspaced, short palindromic repeat (CRISPR) technology capable of making precise targeted changes in the genome of living cells appeared recently [57], and can be the next great opportunity for genetic manipulation of seed vigor. Coming out of this is the CRISPR-Cas9 which is the latest borderline technology based on a bacterial CRISPR-associated protein-9 nuclease (Cas9) from *Streptococcus pyogenes* [58]. This has already been successfully used to target important genes in many cell lines and organisms. The simplicity of this method lends it to wide applications in biology, currently, it is possible to introduce single point mutations (deletions or insertions) in a target DNA with a guide RNA (gRNA) [59]; and induce large genomic re-arrangements, such as inversions or translocations with a pair of gRNA-directed

**Species Methodology Outcome Reference**

The physiological role of *AtPIMT1* in seed vigor and longevity has been Ogé et al*.* [22]

Verma et al*.* [13]

Wei et al*.* [16]

Petla et al*.* [14]

The higher PIMT1 amount in *pimt1–1* seeds correlates with lower isoAsp accumulation *in vivo* and increases both seed longevity and germination vigor,

The role of *CaPIMT2* in seed vigor and longevity has been elucidated *CaPIMT2* enhances seed vigor and longevity by repairing abnormal isoAsp

The role of *OsPIMT1* in seed vigor and longevity has been elucidated

Germination % after 21 days of CDT, overexpressing *OsPIMT1* transgenic seeds, increased 9–15%; *OsPIMT1* RNAi lines, rapid loss of germination.

Transgenic rice and *Arabidopsis* lines with altered expression of *OsPIMT1* and

Germination % after 4 days of CDT, control seeds, 8% (maximum); *OsPIMT1*, *OsPIMT2*, and *OsPIMT2* transformed

in the seed nuclear proteome

established in *Arabidopsis*.

and *vice versa*

*OsPIMT2*

seeds, 43–48%.

**Table 2.** Seed vigor outcomes of different PIMT gene alteration methodologies from different reference sources in

*Arabidopsis thaliana* T-DNA insertion line with

272 Advances in Seed Biology

*Cicer arietinum* Seed-specific over-expression

*Arabidopsis*

*O. sativa* Overexpressing *OsPIMT1* lines

*O. sativa* Transgenic rice and *Arabidopsis*

various crop species [34].

increased *PIMT1* expression and transgenic lines with altered *PIMT1* expression

of *CaPIMT1* and *CaPIMT2* in

and *OsPIMT1* RNAi lines

lines with altered expression of *OsPIMT1* and *OsPIMT2*

risk as food and feed and ethical issues of GMO seeds for innate vigor.

On a global scale, modern agriculture is currently pressurized to achieve food security with limited arable land due to the changing climate and increasing global population. For increases in crop yields with reduced inputs. This paper reviews the state of the art *-omic*s results on seed vigor and offers insights towards up-scaling the laboratory results to field productivity. From the reviews, several biological studies that dissect seed vigor traits in crops are discussed narrowing down to few *-omics* approaches offering possibilities for genetically improving seed vigor by plant breeding. Availability of numerous candidate genes and/or proteins along with enormous seed-specific genomic libraries and high-precision *-omics* techniques like CRISPR-Cas9 constitute new resources for drastic improvement of the trait. One strategy mentioned in this review is genetic manipulation of a number of genes controlling cellular repair, protection, detoxification and enhanced membrane integrity in crops. In the near future, studies on reverse genetics coupled with high precision genetic engineering tools, will lead the way to breeding high vigor phenotypes of many crops on large-scale. The results are expected to produce exciting *-omics* contributions to the advancement of crop yields with less environmental damages when these techniques are up-scaled for agricultural applications. Application to important cereals such as wheat, rice, and maize may have a dramatic impact on global food security.
